The Under Development page has been updated with a synopsis of what the upcoming Patch 3.2 major content patch will offer players.  A new Battleground named Isle of Conquest, more Argent Tournament quests, and the completion of the Argent Colliseum.  Sadly, no mention of the mysterious new dungeon.

We have a poll to see what fans think it might be.

The upcoming major content patch, Call of the Crusade, will bring a host of new features for World of Warcraft: Wrath of the Lich King.

  • The Argent Tournament Expands: With the help of Azeroth’s heroes, the Argent Crusade will finish the Argent Coliseum just in time to call for all brave citizens to prepare for battle with the Lich King. New dailies, rewards, and more will be available at the Argent Tournament grounds to lure adventurers into the coliseum.
  • Crusaders’ Coliseum: In order to prepare for a siege on Icecrown Citadel, players will be called by the Argent Crusade to test their mettle in the Coliseum. 5-player, 10-player, and 25-player challenges await inside.
  • New Battleground: Isle of Conquest, a new large-scale siege Battleground, will be open. The Horde and Alliance will battle head-to-head for control of strategic resources to lay siege to the keeps of their opponents.
  • New Arena Season: Season 7 will officially start, paving the way for all-new items and challenges.
Blizzard Quote:
Zarhym: Yes, there will be a 5-player version, then a 10/25-player version. The bosses will be different for the two versions. Think Ring of Blood or Amphitheater of Anguish, but more epic. If anything, Wintergrasp combined with Alterac Valley with a few more twists. More to come later!