Most of the changes listed below are from blue posts on the official forums. The list will be updated once the official patch notes have been released.
There are no plans for a Patch 2.5.0.[1]
General
Maximum daily quests per day increased to 25. [2]
The Shattered Sun Offensive is Shattrath City's answer to Kael'thas's operations in the Sunwell; it is comprised of the combined forces of the Aldor and the Scryers, led by the naaru.[2]
Spell Haste: Spell haste now reduces the global cooldown on spells, down to a minimum of 1 second. This change does not apply to melee and ranged abilities.[3]
Characters will now retain talented spell ranks so when they retalent they do not have to relearn the spells from trainers.[4]
New teleportation portal to the Caverns of Time accessible through reputation with Keepers of Time [2]
PvP
Battlemasters are now standing on platforms with collision around them.[5]
Diminishing Returns removed from Honor Kills [6]
Honor calculations will become instant rather than daily [6]
If a player has Resurrection Sickness, they are not worth any honor [6]
If a player is killed 50 times in one battleground, they are not worth any honor for the duration of the Battleground [6]
Shadow Sight is now going to increase damage taken by 5% rather than dealing damage over time. The duration has also been reduced from 21 seconds to 15 seconds.[7]
New repeatable Battleground quests [2]
Alterac Valley
The Horde's starting tunnel has been moved back to a more equal distance from the first objectives, which will help evenly distance the starting points for each side across the terrain when the battle commences. [8]
The General and Warmasters for each faction will receive a stacking buff from each other that boosts their health and damage. The more of them that are still in the battleground, the more dangerous they will all be. This will put a greater focus on destroying (and defending!) the towers that remove the Warmasters as players work toward defeating the appropriate General and conquering the land.[8]
Balinda Stonehearth has been studying her spellbooks to become a more challenging opponent to the Horde and will do more damage with her spells. The additional health we recently added to Balinda and General Vanndar Stormpike will no longer be needed with these improvements and will be changed back to their previous amounts with the patch.[8]
Items
Players will now be able to purchase level 70 Superior quality PvP items from reputation vendors.[4] (Reputation vendors in Outland.) [9]
Items intended for Retribution Paladins have had their stats adjusted. Retribution Paladins should see an increase in dps as a result.[4]
Players can now only carry 80 Conjured Manna Biscuits at a time. [10]
New Heroic Badge rewards.[2]
User interface
GM messages now appear with a Blizzard icon near their name.[11]
When looting Bind on Pickup items, the confirmation dialogue now lists the name of the item in the dialogue. You can now verify that you are picking up the correct bind on pickup item.[12][11]
Bind on Pickup items that only you can pick up (Heroic Badges for instance) will no longer bring up a confirmation dialogue.[13][11]
The profession UI search field has been improved and now allows for searching of more types of things. For instance you can search for items by socket color, by effect ("Critical Strike" for instance) or search gems by their effect ("Strength" for instance). In addition, the searching of items by level has been made more intuitive. You can now search for items by level with "15-20" to search for items that you can make that have a minimum level required of 15 to 20.[11]
Various improvements will be made to the combat log.[14][15]
Various improvements to the Interface Options window. [16]
Classes
Druid
Lacerate now deals additional damage based on your attack power. [17]
Mage
Spellsteal will no longer overwrite a longer duration buff.[18]
Priest
Prayer of Mending's overwrite has been fixed.[19]
Priests are now able to use Fear Ward in Shadowform. [20]
Shaman
Healing Grace will reduce the chance that all of your spells will be dispelled by 10/20/30%. [21]
Warlock
Patch 2.4 will remove the restriction for Ritual of Summoning that prevents players from summoning players into instances. Provided the player meets the instance requirements, you'll be able to summon them in from anywhere in the world.[22] The summoning restriction has also been lifted from Netherstorm. [23]
Warrior
Off-hand weapon critical hits from Whirlwind trigger Flurry and Rampage which should improve damage a bit.[24]
Endless Rage will provide significantly more rage. [25]
Professions
Cooking
Recipes for Charred Bear Kabobs and Juicy Bear Burgers have been added and are purchasable from either Bale or Malygen in Felwood. They use meat added to level 48-56 bears, and they will require 250 skill to learn.[26]
Juicy Bear Burgers require level 45. Use: Restores 1933 health over 27 sec. Must remain seated while eating. If you spend at least 10 seconds eating you will become well fed and gain 14 Spell Damage for 15 min.[27]
Charred Bear Kabobs require level 45. Use: Restores 1933 health over 27 sec. Must remain seated while eating. If you spend at least 10 seconds eating you will become well fed and gain 24 Attack Power for 15 min.[27]
Enchanting
Added a recipe to convert a [Void Crystal] into two [Large Prismatic Shards] with a likely 24 hour cooldown.[28][29]
Fishing
New Fishing Daily Quests! Visit the mysterious old man fishing at Silmyr Lake outside of Shattrath City to discover what treasures he has to offer.[30][29]
Mining
The various types of ore will be adjusted so that you can consistently level up your skill from the nodes available in the zones where your character will be leveling, without you having to go back and spend lots of extra time in areas where you don't have any quests.[31]
Dungeons and raids
All 25-player raid bosses that drop set tokens will now drop an additional token![32]
All 25-player raid bosses will now drop more gold.[32]
Gems obtained through Heroic difficulty instances are no longer Unique-equipped. [33]
Loot dropped by Doom Lord Kazzak and Doomwalker has been changed to Bind on Equip. In addition, the cash dropped by these bosses has been significantly increased.[32]
Scale of the Sands reputation will now be awarded in Hyjal at a much higher rate. [32]
Magister's Terrace
5-Man instance with Heroic (Kael'thas is a confirmed boss.)
Sunwell Plateau
Sunwell Plateau will be a 25-Man raid[34] available at level 70 with a difficulty of the Black Temple or higher. All drops will be above Tier 6. The instance will be designed in the same style as Silvermoon.
Environment
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Sunwell Isle
The Sunwell Isle will be, according to Blizzard, "a cool 'public' area featuring brand new daily quests" shipping in Patch 2.4.[35]
Source: WoWWiki.com
