With the updates to the Onyxia encounter in patch 3.2.2, this boss now resets every Tuesday like most raid instances. There was an issue when the patch first launched where an incorrect reset timer was listed. This has been resolved and Onyxia will reset next Tuesday as intended. (Source)

Cataclysm
Cataclysm release date
There is not yet a release date for Cataclysm. (Source)

Patch 3.3
Patch 3.3 Information
We're preparing some information to share with you about patch 3.3. You'll just have to stay tuned for that. I can say though that the five-player dungeon portion of Icecrown Citadel is absolutely epic and essential to the unfolding story of the Lich King and your battle to end his wrath.

Vehicle Fights in Icecrown Citadel
There will be no vehicular or mounted combat in the dungeon. [...] We talked at BlizzCon about an airship battle involving the Horde and Alliance ships in Icecrown for the raid, but this isn't really a vehicle fight comparable mechanically to those found in Ulduar, Wintergrasp, Isle of Conquest, or Trial of the Champion. (Source)

Icecrown Dungeons
That isn't our philosophy. We're carefully designing three separate wings of a sprawling five-player dungeon -- the largest we've released in a long time -- precisely so that a majority of our end-game player base can take part in an epic experience. You'll see plenty of significant areas, heroes, and foes in Icecrown Citadel without having to set foot in the raid. (Source)

[...] The five-player dungeon is completely separate from the raid dungeon. It's not a five-player version of the same content. (Source)

Patch 3.2.2
Changes to Alterac Valley in 3.2.2
It was explained in the sticky on the PvP Discussion forum. Unfortunately, a change to the level brackets for Alterac Valley made it into a build for patch 3.2.2 when it was intended for patch 3.3. Because of this the NPCs were not properly tuned for select level brackets. Given that this change was going to happen anyway, we made the decision to keep the level bracket change since it already went live and address any adverse affects as they arise. (Source)

Requirements for holiday achievements
Some holiday achievements require near maximum-level PvE content. This remains so even if people aren't inclined to reach maximum level.

Some holiday achievements require players to go into battlegrounds. This remains so even if people aren't inclined to get honorable kills on their character.

And, yes, some holiday achievements require skill in a secondary profession, and we have no plans to change that.

The holiday achievements are not necessary to advance your character. If you want a title or the mount reward at the very end of What a Long, Strange Trip It's Been, however, you will have to participate at least marginally in all these aspects of the game.

The holidays are designed to allow a large breadth of the playerbase to participate in some form, and there's normally something for you to do within the holiday itself. How much you choose to participate is up to you. If you choose to pursue the achievements, then you will have to participate in all these aspects of gameplay. That is absolutely by design and not something we plan to change currently.

That said, if leveling your cooking for Winter Veil seems like a tedious task, I suggest you wait until Pilgrim's Bounty.... (Source)

Onyxia too easy?
The new Onyxia is meant to be more of a celebration of the 5 years of World of Warcraft and not a progression encounter. The way it is setup is for as many people as possible to still enjoy in the game and get some extra bonus loot/emblems/bags/gems on top of that.

On top of that, players certainly understand the game much better now than they did when Onyxia first came out. This became pretty clear when people didn't get much better gear but were able to kill her with fewer and fewer players even at level 60. (Source)

Arthas in Warcraft 3
Warcraft 3 really established Arthas in the position of the Lich King in its expansion - The Frozen Throne. His relevance is not to be trivialized, but to say that we have established him as "The Big Boss" is a bit of a stretch. Warcraft 3 introduced a whole new level of threat to Azeroth - The Burning Legion. There have been some encounters with them and their powerful masters, but I'd hesitate to say that they've been "defeated" once and for all. We've also seen the rise of old gods such as Yogg'Saron and C'thun and I'm sure you're aware of the impending return of Deathwing. There is a whole slew of lore characters who haven't been around and thousands of plots and intrigues that have been developed throughout the lifespan of World of Warcraft and its expansions. Many big nasty bosses have been slain and still the problems of the world have not been alleviated. Perhaps, just maybe, there is more going on then one can gather in a glimpse. (Source)

Shaman
Blodlust / Heroism
Bloodlust / Heroism is a very strong buff. No argument here. I can understand the point of view of players who think other specs need to offer it. Currently three specs offer it, but they are also specs that fill relatively different roles. The fact that all three specs belong to one class makes it a special case.

In general, we balance 25 hard mode content assuming you have 1 shaman for Bloodlust or Heroism. We balance 10 hard modes without that assumption, though you still need to have a reasonable mix of the stronger buffs. We don't think that typically replacing a good say mage with a bad shaman will turn a failure into a success, but each group is a little different so it is possible. (Source)

There will be no vehicular or mounted combat in the dungeon.