Dungeons & Raids
Hour of Twilight

• Archbishop Benedictus
  
  • Thrall should no longer despawn when no players are near him after the gauntlet has been completed.
    

Throne of the Four Winds

• Al'Akir
  
  • Wind Burst should no longer knock players back too far.
    

Dragon Soul

• Morchok
  
  • Earthen Soldiers, Ancient Water Lords and Earthen Destroyers now move faster.
    
  • Morchok's Resonating Crystals should now always target the closest players when they explode.
    
  
  
• Yor'sahj the Unsleeping
  
  • Damage done by Forgotten Ones, Void Bolt AOE, and Searing Blood has been reduced on 25-person, Heroic difficulty.
    
  • Yor'sahj's health has been reduced by 10% on 25-person, Heroic difficulty.
• Hagara the Stormbinder
  
  • Hagara’s Frost Shield can no longer be broken by Shattering Throw to avoid her Frozen Tempest phase.
    
  
  
• Warlord Zon'ozz
  
  • Disrupting Shadows no longer deals AoE damage or knockbacks when the duration is reduced with Mage Armor on Heroic raid difficulties.
    
  
  
• Warmaster Blackhorn
  
  • Shockwave can now be broken by trinkets and other effects that cancel stuns.
    
  • Blackhorn's Vengeance now accrues at a rate of 1% per 2% of missiong HP on Raid Finder difficulty.
    
  • After Warmaster Blackhorn is killed, the deck fire on upper decks is no longer present on Heroic difficulty.
    
  • Warmaster Blackhorn, the Twilight Elite Slayers, and the Twilight Elite Dreadblades are no longer able to attack players while mounted.
    
  
  
• Spine of Deathwing
  
  • Blood Corruption: Earth will no longer morph into Blood Corruption: Death when dispelled.
    
  • Blood Corruption: Earth now applies two stacks of Blood of Neltharion when it expires on 25-player heroic difficulty.
    
  • The health pools for Burning Tendon, Corrupted Blood, Corruption, and Hideous Amalgamation have been reduced by 6 to 11% for 25-person raids on both normal and Heroic difficulty.
    
  • Hideous Amalgamations with the Superheated buff no longer pulse their AE damage after being thrown from Deathwing's back.
    
  
  
• Madness of Deathwing
  
  • Damage done by Elementium Blast, Corrupted Blood, and Blistering Heat have been lowered on Raid Finder difficulty.
    
  • This encounter should now complete when all players die after Deathwing has been defeated.
    

Items

• Darkmoon Zeppelin should no longer be converted to a Horde Balloon during an Alliance to Horde faction change.
  

Classes
Druid (Forums / Talent Calculator / Skills/Talents)

• Pounce should now apply its Bleed to targets beyond its normal range when used with the Glyph of Pounce.
  
• The Mass Regeneration effect from the Druid Tier 13 bonus now heals 25% of the healing received by the Druid from Frenzied Regeneration, down from 50%. The tooltip will be updated in a later patch
  

Paladin (Forums / Talent Calculator / Skills/Talents)

• Holy Radiance should now stack properly with Holy Radiance, with all valid targets nearby being properly healed.
  

Warrior (Forums / Talent Calculator / Skills/Talents)

• Bladestorm will now properly apply its immunities to spell effects that are in flight when Bladestorm is activated.
  

Transmogrification Rules
As mentioned in the original post, mailing an heirloom to your alt will strip any transmogrification effect. There was a bug that sometimes prevented this from happening, but it is now fixed. (Blue Tracker / Official Forums)

LFR 10 Man Size
Having the LFR group size set at 25 allows for a more forgiving experience should errors be made by individual players — after all, we believe Raid Finder groups should be a fun way to experience raid content without feeling too punishing to new or inexperienced raiders.

In regards to the loot issues you mention, such as people winning the same item twice, we're working on a solution for this. (Blue Tracker / Official Forums)

Different Deathwing Endings for Different Difficulty Levels
In terms of storytelling and content accessibility, there isn't a real difficulty. The way we handled Ragnaros was kind of unique, but he's not the final boss of this expansion.

Your idea is quite contrary to our motivation for implementing multiple difficulties. We want as many people as possible to be able to experience the story, while still preserving many of the more prestigious rewards and achievements for those who complete Heroic difficulty. (Blue Tracker / Official Forums)

Why do we have to pay real money for pets/mounts?
Pets and mounts are entirely cosmetic, they don't give you any in-game benefit or edge over others, therefore they're not needed, and the statement that they're "much better" than the ones in the game is completely subjective.

There are some rare pets and mounts in the game that are only obtainable from certain quests or encounters. If you prefer collecting things through the game, you could focus on getting all of those. (Blue Tracker / Official Forums)