As more information gets revealed about the upcoming expansion to Guild Wars 2 some of the information has started to get lost and forgotten, which has lead to some rather depressing debates on various forums. I have put together the following list (and sources) to help everyone keep track of the information better and help the general discourse be a bit better informed. All of the information I am including here is information Arenanet has either released themselves or has confirmed as being true. As a result some information we only know from datamining is not listed.

Aside from questions about what we do know for sure a big sticking point for many people has been “what content will everyone get and what content will only be available if you buy the expansion?” To help with this I have come up with the following color coding system:

Things you can only access if you personally have the expansion

Things you can experience if you play with someone who has the expansion or can have limited access to without buying the expansion

Things I think will be locked to the expansion but Arenanet hasn’t confirmed yet

I’ve done my best to gather all the official information I could find, if  I missed anything please let me know (and ideally give me some way to find the official source). I haven’t had time to go back through the PoIs and Ready Ups so anything revealed on those isn’t currently included.

Launch date October 23, 2015! (source)

The Heart of Maguuma Region (source)

• Four new maps, all with increased virticality (source)
• Jungle made up of 3 biomes (source)
  • Roots, Floor, Canopy
• Find Glint’s Legacy (source)
• New types of content and new challenging content (source)
• The Verdant Brink is the map where the expansion will start (source)
• The first map (source)
  • Handles what happened to the Pact Fleet
  • Build defenses during the day
  • Mordrem will come out at night and it will be a fight for survival
• Each map will be focused on 3D play space and provide high replay value (source)
• Outposts (source)
  • Events will be tied to what is happening at a specific site
  • Results of localized events will be shown through what happens at the outposts
  • The night phase challenge in the first area are wyverns
  • Make as much progress as possible during the day to have a chance during night time
  • Some out posts will have multiple upgrades which will make them stronger and offer new rewards
• Adventures (source)
  • Repeatable on-demand bits of content
  • Will require practice, mastery, and skill to master (source)
  • Will unlock as progress is made at an outpost
  • Have their own UI and offer some amount of active challenge
  • Progress through an adventure will be tracked and scored; players will be able to see the scores of friends and guildmates
  • Will be displayed on the world map
  • If an adventure isn’t currently open, there will be an explanation of how to open it in game
  • Other players will have no impact on success or failure, ie won’t have to compete for resources or objectives (source)
  • Will be reliant on patterns and systems players can figure out to improve their play (source)
  • Players will be able to quickly quit and restart with minimal downtime (source)
  • Each adventure has its own distinct separate leaderboard (source)
    • Each leaderboard has daily participation rewards
    • Leaderboards will be divided into three tiers and the first time a player moves into one of those tiers they will receive a bonus reward
    • Higher tiers have higher rewards
• Story instances will be replayable and players will be able to make different choices when they replay (source)
  • These will also have difficult to obtain achievements (similar to Living Story Season 2) and they will yield Mastery Points
• Player character will be speaking in the open world as well as in story instances (source)
  • Lines will also vary depending on race of the player character
• Two new armor sets to work on in the open world content, 5 new weapon sets, 60 additional unique skins, miniatures, and more (source)
• New map rewards (source)
• If you own the expansion you’ll be able to gain access to upcoming new living story (source)

Raids (source)

• First raid will have three wings, the first of which will open up a few weeks after HoT launches
  • The delay gives time for balance passes to be done on professions and the new elite specs
  • Also players will have time to earn some of the mastery abilities they’ll need to beat the bosses
• The remaining two wings will be opened in sequence after, depending on how quickly players are moving through the first wing
• The first wing will have three bosses
• First wing will require players to have unlocked gliding and a few different ways to interact with mushrooms (source)
• 10 Player instanced content
• Uses the event system which allows for greater variety of mechanics and tactics to be used
• Players will need to be highly coordinated to beat these bosses
• There won’t be a traditional raid frames set-up, players will have to communicate and pay attention each other to make sure they can down bosses
• There will be new Mastery Tracks and Abilities which will be tightly tied to boss mechanics
• Will be how players get Legendary Armor (source)
  
• Old raids won’t become a wasteland of irrelevance
• In addition to boss fights there will be event styled things for the group to accomplish IE holdouts, assaults, captures, defends, etc (source)
• Encounters are designed to push players to use a variety of builds, weapons, and armor types (source)
• Groups will use the squad system (source)
• Can earn unique rewards once a week (source)
• Some types of rewards exclusive to raids are special minis, weapon skin, titles, and a special trophy for your guild hall (source)

Mastery System General (source)

• Account bound PvE progression system
• Reinforces the idea the journey is the main goal (source)
• Gain Mastery Points as you complete content (source)
  • Completing elements of the Story
  • Reaching hard to find & hard to reach locations
  • Defeating “incredible” challenges and “incredible” group challenges
  • Map completion
  • Challenging achievements “across the jungle and beyond”
  • Each point can be obtained once per account (source)
  • Players will be able to earn Mastery Points before lvl 80, but won’t be able to spend them until after (source)
  • Points gained in an area can only be used to unlock Masteries in the same area (source)
  • A good number of points earned before HoT will be awarded to players with the release of the expansion (source) (more info)
• Experience bar will change to the Mastery Training bar at lvl 80 when in PvE zones (source)
  • To train a Mastery you will have to first unlock it by spending a Mastery Point
  • Each unlock will have multiple tiers with more powerful abilities in each subsequent tier
  • Select the Mastery to be slotted on the Mastery Bar and then any experience gained will be put towards increasing the mastery level
  • Players will set their active Mastery by region and the bar will automatically switch when the player changes regions
• Exploration Mastery (source)
  • Hang gliding
    • Higher tiers allow for longer flights, ride wind currents, jump higher, and launch into the air with greater force (source)
  • Ability to use mushrooms to move around The Heart of Maguuma faster (source)
• Lore Mastery (source)
  • Learn to understand the languages of civilizations deep in the jungle
  • Gain access to hidden locations only people who understand the language will be able to access
• Combat Mastery (source)
  • Will allow players to learn new abilities which will help them overcome challenges
  • Master abilities to defeat champions (source)
  • Become more deadly to the new creatures in the jungle (source)
• Legend Mastery (source)
  • Learn to craft current precursors (source)
  • Learn to craft new precursor for the new legendary weapons
  • Current precursors (source)
    • Three tiers
    • Visit Mastery vendor to pick which to start
    • First tier focuses on one theme of the Legendary
    • Completing the first collection will unlock the ability to craft a “distressed” version of the precursor and won’t be tradable
    • The second collection will focus on doing research about the legendary, which will unlock another exotic non-tradable version of the precursor
    • The third collection will focus on the secondary theme of the legendary weapon and will yield the recipe for the final version of the precursor
    • Will be tradeable
    • Skins will be updated to look like “lesser” versions of the legendary weapon they create
    • Having any version/step of a legendary will automatically unlock all previous skins attached to it
    • Will only be able to craft one of each precursor per account this way
    • All current methods of obtaining a precursor will remain intact
  • New Legendary Weapons and their precursors will not be tradable (source)
  • New precursers will not drop anywhere in game (source)
  • New Legendaries which will be available to make shortly after HoT launches along with raids (source)
  • The first three will be Astralaria (Axe), H.O.P.E. (Pistol),and Nevermore (Staff) (source)
  • Recipies to craft the new legendaries will be the specific precursor, a Gift of Maguuma Mastery, a Mystic Tribute, and a unique gift associated with each legendary (source)
• Fractal Mastery (source)
  • New depths in the Fractals
  • Gain new abilities for use in the Fractals
  • Get better rewards
  • Unlock more powerful infusions

Specific Mastery Lines

• Gliding (source)
  • Glider Basics
  • Updraft Use
  • Lean Techniques
  • Stealth Gliding
  • Advanced Gliding
  • Ley Line Gliding
• Itzel Lore (source)
  • Bouncing Mushrooms
  • Itzel Language
  • Blazing Speed Mushrooms
  • Itzel Poison Lore
  • Itzel Leadership
  • Adrenal Mushrooms
• Exalted Lore (source)
  • Exalted Markings
  • Exalted Acceptance
  • Exalted Assistance
  • Exalted Purification
  • Exalted Gathering
  • Exalted Honing
• Nuhoch Lore (source)
  • Nuhoch Hunting
  • Nuhoch Language
  • Nuhoch Wallows
  • Nuhoch Stealth Detection
  • Nuhoch Proving
  • Nuhoch Alchemy
• Legendary Precursor Crafting Mastery (source)
  • Revered Antiquarian
  • Magister of Legends
  • Historian of the Armaments
  • Scholar of Maguuma’s Secrets
• Tiers in Fractal Mastery (source)
  • Follows Advice
  • Agony Channeler
  • Mistlock Singularities
  • Recursive Resourcing
  • Essential Singularities
  • Hyperactive Singularities
• Pact Commander (source)
  • Pact Mentor
  • Productive Downtime
  • Supply Line Management
  • Noblesse Oblige
  • Advanced Logistics

Elite Specializations (source)

• Every profession will get an Elite Specialization/Secondary Profession
• General Elite Specialization info (source)
  • Will always introduce a single new weapon type for a character
  • To use the new weapon or skills, players will have to both unlock and equip the Elite Specialization
  • Almost every Elite Spec will get a new heal, utility skills, and elite skill
  • Will make core changes to how a profession is played
  • Has a full set of new traits
  • When HoT hits each profession will get one Elite Spec
  • Only one Elite Spec will be allowed to be equiped
  • Unlocking an Elite spec will also grant new runes and sigils, a fancy weapon skin for your new weapon type, and an armor skin for a single matching piece of armor (usually headgear or shoulders)
  • Elite Specs will automatically be unlocked in PvP
  • Will need to have core lines completly unlocked before being able to unlock any of the Elite Spec (source)
  • It will take 400 points to unlock an Elite Spec fully (source)
  • Hero Challenges in the Jungle award 10 points instead of one (source)
• Ranger’s elite specialization will be Druid (source)
  • Allows use of Staff
  • A new heal skill
  • A new elite skill
  • A new set of utility skills
  • New resource called astral force which is used to enter the new Celestial Avatar form (source)
  • Celestial Avatar substantially boosts the healing abilities of the Druid (source)
• Necromancer will get Reaper (source)
  • Allows use of Greatsword (source)
  • Grants a completely new set of abilities in death shroud and creates a shadowy scythe when entering death shroud
  • Death’s Charge replaces Dark Path and causes the Reaper to dash forward dealing damage as you go and releases a poison cloud at the end
  • Shivers of Dread inflicts chill whenever fear is used
  • Cold Shoulder increases the duration of chill and reduces the amount of damage chilled enemies do to you
  • Most attacks will be slower, but will also hit much harder than you might otherwise expect
  • Gravedigger is a slow skill which delivers a devastating blow to all enemies nearby
  • Reaper will also get a full set of shouts focused on harming foes
  • Rise is a shout which will hit all enemies in the radius for a small amount of damage and will summon a jagged horror for each foe struck
• Mesmers will get Chronomancer (source)
  • Will gain use of Alacrity which will speed up skill recharge times
  • New weapon is off-hand Shield
  • Tides of Time – destroys projectiles, stuns enemies, and granting quickness to allies
  • Gain access to time themed wells
  • Well of Precognition – causes the attacks of allies to become unblockable and when it ends allies can evade all incoming attacks
  • Continuum Split/Continuum Shift is a new Shatter mechanic which allows the Mesmer to revert time and undo everything which happened to them during that time
• Guardian will get Dragonhunter (source)
  • Focuses on ranged combat and back line support
  • Allows the use of Longbows
  • Spear of Justice – Virtue of Justice becomes a thrown spear which will tether enemies as long as they remain in range
  • Wings of Resolve – Virtue of Resolve will become wings of light which will allow the player to leap to an area and heal allies and can be traited to also deal damage
  • Shield of Courage – will allow attacks to be blocked for allies
  • Abilities will retain passive properties conferred by traits
  • Will have trap skills
  • Heal trap will heal allies while simultaneously heal allies when the Guardian triggers it
• Elementalists get Tempest (source)
  • Allows use of Warhorn
  • Adds full set of 6 shouts
    • Wash the Pain Away – heals allies and cleanses conditions
    • Feel the Burn – Causes flames to erupt from a specific location
    • Eye of the storm – calls down a storm which breaks stuns and grants superspeed
    • Aftershock – creates a force around the Tempest which will cripple enemies and after a delay it will immobilize them
    • Freeze – freezes air around enemies damaging and chilling them
    • Rebound (elite) – causes all allies around the Tempest to have a 25% reduced recharge on their next ability used
  • Adds Overload mechanic to attunements
    • Overload Fire creates an infernal tornado which continuously damages and burns enemies while giving allies might
    • Overload Water creates a bubble which will grant regeneration and cleanse conditions from the Tempest and allies, when it end the bubble will burst and provide a large heal to allies in the area
    • Overload Air creates a nimbus cloud which strikes enemies repeatedly, at the end of the ability it will leave behind a lightening field
    • Overload Earth rends the earth and grants protection to allies and cripples enemies, at the end of the ability it’ll deliver a large blast of damage
  • Overloads will cause a longer than normal lockout of an attunement
• Revenants get Herald (source)
  • Allows shield as an off-hand weapon
    • Envoy of Exuberance – Glint’s energy shoots out healing allies and grants protection on the way back
    • Crystal Hibernation – Channel a shield that renders the player immune to damage and gives a heal
  • Legendary Dragon Stance (Glint) – Support via boons, utility, and personal defense
  • Facets of Glint Utility Skills (all are upkeep skills)
    • Facet of Elements – Grants a pulsing swiftness buff
    • Elemental Blast – Ground targeted skill which consumes Facet of Elements and applies conditions to foes
    • Facet of Chaos – grants nearby allies protection every few seconds
    • Chaotic Release – consumes Facet of Chaos and grants super speed to allies while also damaging and knocking back foes
    • Facet of Nature – Pulses every few seconds and increases the outgoing boon duration for allies
    • One with Nature – Consumes Facet of Nature and applies boons all the other facets would apply to allies
• Warrior gets Berzerker (source)
  • New weapon is torch
    • Blaze Breaker – send a cascade of rock and flame which travels to your target, crippling and burning any foe in the way.
    • Flames of war – Light yourself on fire burning off any conditions and creating a fire field that follows you. When the effect ends it explodes a applies more burning to foes around you.
  • At max adrenaline the bar will change to a single bar with only 10 adrenaline (instead of the normal three tiered bar with 30 adrenaline)
    • Give new weapon burst skills which can be used more often
    • Scorched Earth (longbow) – leaves a trail of fire on the ground in a straight line, is an aimed skill
    • Skull Grinder (mace) – short disrupt and applies multiple conditions to your target
  • Primal bursts are considering tier 3 bursts for traits
  • Feel the Rage – new type of utility skills called rage skills
• Thief gets Daredevil (source)
  • Gains the use of Staff
  • Highly mobile fighter who is capable of taking on multiple enemies at once
  • Will have an extra endurance bar
  • Grandmaster trait line enhances dodge options
    • Lotus Training – each dodge throws daggers which cause bleed, torment, and cripple to foes and additionally functions as a whirl finisher
    • Bounding Dodger – gives the ability to leap in a specific direction and deal crushing damage where you land, additionally it functions as a leap finisher
    • Unhindered Combatant – Dodge becomes a dash which increases the distance you dodge and removes cripple and chill effects from you
  • Channeled Vigor – pulses heal and endurance regen, also heals for an additional amount if endurance is full

Revenant (source)

• Ability to channel and control the Mists (source)
  
• Heavy Armor
  
• Uses energy as a resource (source)
• Will use Hammer as a ranged weapon (source)
• Can us Mace in the main hand (source)
• Can use Axe as off-hand (source)
• Can use Staff as a melee weapon (source)
• Will be able to use Sword in main hand and off hand (source)
• Will have weapon swapping (source)
• On swap sigils activate when switching Legends (source)
  
• Will use Spear underwater (source)
• Use of Great Legends of Tyria
  • King Jalis – Tanky, Brawly Playstyle
  • Malyx – Conditions
  • Ventari – Support and Healing
  • Shiro – physical mobile dps

New WvW Borderlands Map (source)

• Each Keep has a separate theme
  • Earth keep will raise up to defend itself against attackers
• Fire Keep (source)
  • Located entirely underground
  • Has lava pools surrounding it
  • Fire imps and charred fleshreavers guard it
• Air Keep (source)
  • Cut into the walls of the cavern
  • Has Tengu guarding its heights
• Earth Keep (source)
  • Corrupted asuran complex
  • Has rock formations and boulders floating in the air
  • Golems are the guardians
• Holding a keep will give buffs to the world which has it
• There will also be changes to core WvW
  • Holding objectives should be a bigger component of victory
• Will have 3 Keeps, 4 towers, and 6 supply camps (source)
• The towers are an ogre outpost, a charr military depot, an academy of magic, and a necromantic spire (source)
  • Towers will actually create choke points and be of strategic importance
• The gates of towers and keeps will be more lethal to attack head on (source)
• Shrines (source)
  • Outside each keep
  • Three shrines of matching elements to the keep they are near
  • Can be capped by a single player
  • Capping the shrines will give buffs and bonuses which will make taking and keeping their keep easier
• Oasis (source)
  • Located in the middle of the map
  • Multilayered and full of all kinds of hazards (including dinosaurs)
  • Players will collect cores to charge up the giant cannon
  • When the cannon fires it will start to fire blasts of energy at all enemy towers and keeps, gradually obliterating their gates
• Dolyaks will gain significant buffs if a friendly player is near them (source)
• Sentries will be guarding tiny outposts and will have a cripple skill to hamper enemy dolyaks (source)
• Players will also be able to pick-up medkits at their outposts and use them to heal dolyaks, gain some health, or grant swiftness (source)

Changes to all WvW maps (source)

• Upgrades will have no gold or supply cost
• Less supply will be held and transported
• There will be upgrade tiers instead of tiers
• Upgrades happen automatically over time
• Camps will have 2 tiers and all other objectives will have 3 tiers
• Higher tiers take longer to upgrade than lower tiers.
• Dolyak shipments will reduce the remaining upgrade time
• Total time needed should be about the same as before the changes
• Changes to WvW Abilities (source)
  • Guard Killer and Defense Against Guards will only have 5 ranks instead of 10
  • Applied Fortitude and Applied Strength will be removed
  • Ability lines which increased percentages from 1% to 5% will increase percentages from 2% to 10%
  • Siege weapon lines and the Supply Capacity line will have a reduced cost
  • All lines which have 5 ranks will cost 35 points per line
  • All lines which have 4 ranks will cost 15 points per line
  • The main player XP bar will change to track WXP when the player zones into WvW
• Players will be able to buy Notarized Scrolls of Heroics and Notarized Scrolls of Maguuma Heroics which will allow players to unlock Hero Challenges through WvW play alone (source)
• Changes are being made to prevent players from stocking up liquid world experience for launch day of HoT (source)

Strongholds (source)

• Fight for Supply
• Spend Supply to help your team
• Players will be able to choose is they prefer Conquest, Stronghold, or Both and will be able to queue for the type they prefer (source)
• Join with heroes to help in the fight
  • Turai Ossa (source)
  • Grymm Svaard (source)
  • Nika (source)
• Kill the Guild Lord
• More Mist Champions will be added through new reward tracks in the future (source)
• Unlocking a Mist Champion reward champion track will also allow players to unlock a second track which will reward that champion’s mini (source)

New sPvP Ranks (source)

• Everyone who owns the expansion will start at Jungle Rabbit rank
• As a rank reward track is unlocked the next one will open up until you reach your current rank, all the way up to Dragon
• Jungle Dragon rank has a new finisher which is Heart of Thorns themed

sPvP Leagues (source)

• There will be six divisions – Lowest level is called the Amber Division and the Highest is the Legendary Division
• Players will be matched up with other players in the same divisions
• Players will earn pips from winning, and when enough are earned they will move up to the next division
• If players are matched against a team outside their skill bracket they will have to reach a certain score threshold to get awarded their pip
• Crossing into a new tier or new division will earn bigger and more prestigious rewards (the first time in a season this is done will give the biggest rewards)
• The Amber Division will only award pips, it won’t take them away for losing
• In divisions two and three players can lose pips but they won’t lose tiers
• Starting in division four players can lose both pips and tiers
• During a season players will never fall back to a previous division
• The sixth division (Legendary) is a repeatable division which plays can fill out for repeatable rewards
• Different divisions will have different badges for player nameplates
• Badges are earned for each current season; as soon as a new season starts all badges are reset and must be earned again
• Anyone who makes it into the Legendary Division will earn a permanent title
• League Tokens are a reward for crossing into higher divisions and can be used to buy the first level of the “Wings of Glory” back item and can be used to upgrade it
• New items will be added in the future and the newest items will always be at a discount
• League play will also unlock the ability for players to craft a precursor and eventually craft that item into a legendary back item
• Dishonor system will be returning
• Guild Teams in sPvP (source)
  • A guild team is a named five player group who compete in sPvP together
  • Each team will have their own rating and place on the new guild leaderboard
  • A single guild can have multiple teams but each must have a unique name
  • Each team will have one captain
  • Must have 3 members of a team queuing together in order for a match to be counted as a team match
  • Matchmaking will use the team rating instead of personal rating when playing as a team
  • Guilds can unlock perks, for example the guild anthem can play at the end of a match the team wins
  • Will be active during all league seasons (source)
  • Ratings will decay with time (source)
  • Rewards will be given at the end of season based on where teams end and will also be used to determine who will be invited to higher-tier tournaments (source)

Guild Halls (source)

• Home base to build & grow
• Core hub for a guild
• Guilds will choose between Lost Precipice and Gilded Hallow (source)
• Claiming your Guild Hall (source)
  • Guilds will register themselves with the Guild Initiative
  • Guild Initiative Headquarters is an instance shared by guild members (sort of like a mini hall)
  • After clearing out the Modrem a Guild Leader will interact with a crystal to claim the Hall
• Building the Hall (source)
  • To upgrade Halls guilds will use a combination of specific crafting materials, favor, and aetherium
  • Aetherium is generated automatically over time from the guild mine
  • Buildings form instantly when you pay for them
  • Six main buildings Tavern, Mine, Workshop, War Room, Market, Arena
• Consumable upgrades which have been purchased should be used before Heart of Thorns goes live (source)
• Once the Guild Initiative Headquarters opens Guilds will be able to trade a limited amount of Influence for Favor everyday (source)
• Influence will also be used to purchase a small increase to aetherium production, once a day (source)
• Guilds will also be able to convert as much influence to resonance as they like (source)
• Merits will be retired (source)
• Heart of Thorns will introduce the ability to view and talk in any guild chat of which you are a member even if you aren’t currently representing (source)
• Guild Mission changes (source)
  • Will be how guilds earn favor
  • Missions will be free to run as often as wanted, but rewards will still be once a week
  • Guilds will start with a few missions available, and as the guild levels up more missions will open up
  • Guild Challenges and Guild Puzzles will be instanced
  • Only one mission of a given type can be active at a time
  • A guild portal in the guild hall can be built and will transport guild members to the start point for each guild mission available
• Guild Crafting (source)
  • Guild Items will have a build time requirement
  • This time can be shortened by using resonance
  • Resonating shards will drop while playing grouped with guildies and is the main source of resonance
  • Scribes can create guild consumables, improvements and tactics for claiming in WvW, and guild hall decorations
• War Room (source)
  • The ability to claim objectives is unlocked through the war room
  • The guild with the most members present when an objective is taken will have first priority in claiming
  • If three guilds pass then anyone can claim
  • Guilds can only have one objective per map claimed (source)
  • Objectives can be claimed by clicking on the objective in the map (source)
  • Claimed objectives will be marked by a shield on the map (source)
  • Upgrades are upgrades to an objective that give it better defenses and new functionality
    • These improvements last for as long as your guild has the objective claimed
    • Tier I unlocks after guild has objective for 10 minutes, Tier II at 30 minutes, and Tier III at 60 minutes (source)
    • Each tier offers options for the upgrades and it will take 3 minutes for the upgrade to be built (source)
  • Tactics are objective-based abilities that players can activate to temporarily boost or defend an objective

Changes to Fractals (source)

• Each fractal run will consist of one fractal from a static list instead of three random fractals with a random boss at the end
• The static list will be dependent on the scale of the fractal (source)
• Lower scales will be adjusted to help new players learn the mechanics
• Maximum fractal scale will be raised from 50 to 100
• Past 50 the difficulty curve will not only adjust health and damage of creature but will also adjust other stats (ex toughness and precision)
• Existing mistlock instabilities will either be updated or replaced
• In the higher scales there will also be multiple mistlock instabilities active at the same time
• Dessa will also have new consumables for fractals available which will stack with other existing consumables
• Fractals will have their own achievement tab and will have special rewards for completing them
• Daily fractal achievements will be divided into three level ranges 1–20, 21–50, and 51 and above
• The final chest in every fractal will be a tradeable lockbox called a fractal encryption which has the chance to contain the following (in addition to other things):
  • Mini Professor Mew
  • new ascended aquatic-breather recipes
  • high-level crafting materials
• Mini Professor Mew can be combined with a fractal ingredient to create the full set of cat golem mintures
• Changes to fractal weapon skins
  • Addition of a collection for obtaining all the skins and a new reward
  • After completing fractal scale 50 golem BUY-2046 will sell a fractal weapon crate for pristine fractal relics and players will be able to pick which skin they want
  • New skins will be added but will only be obtainable at the 50+ scales
  • Will be able to take any of the new fractal skins and convert it, in the mystic forge, to a new fractal weapon skin of the player’s choice
• BUY-2046 will also start selling Ascended Salvage kits
  • Salvaging any ascended item will have the chance to yield a ball of dark energy which is needed for crafting new legendary items
  • Salvaging rings will yield stabilizing matrices, useful for legendary crafting or can be traded in for fractal encryption keys

Legendary Backpacks (source)

• Will be account bound
• A guide in Mistlock Observatory will help point players in the direction of new types of challenges, timed boss encounters, and collections of items to obtain both inside and outside of the fractals
• Those achievements along with armorsmith, leatherworker, or tailor profession will enable players to build their precursor back item
• The last step to making it a legendary item is called Ad Infinitum

Other sources:

About Guild Hall availability: https://forum-en.guildwars2.com/forum/game/hot/Guilds-and-Guild-Halls/first#post5195339

About needing HoT to make a Revenant: https://forum-en.guildwars2.com/forum/game/hot/Have-to-buy-HoT-to-create-a-Revenant/first#post4867494

“The ability to train Masteries is unlocked at level 80 for all players that own Heart of Thorns”: https://www.guildwars2.com/en/news/reimagining-progression-the-mastery-system/

“While elite specializations will be available to everyone who purchases the expansion, the upcoming core specialization changes will affect the base game.” : https://www.guildwars2.com/en/news/ready-up-core-specializations-summary/

About Leagues being tied to HoT, I talked to John Corpening about it at the GW2 Pax party, I’ll update with a link when his new post about Leagues gets posted.