Everyone suspected that this would happen, but nobody wanted to face the facts (including me). : D
Yesterday during a conference call with the investors, Activision Blizzard announced that in Q1 2012 they are not planning to release a new game of Blizzard Entertainment, but there are two, planned to be released by the end of 2012.
Later in the battle.net forums Bashiok kindly explained that the company never told Q1 2012 for Diablo III, but "early 2012": D and this week they decided that they will enter Q2.
So I start to expect Diablo III in June and StarCraft II: Heart of the Swarm at the end of 2012 (although they could comfortably postpone it for Q1 2013) and the World of Warcraft: Mists of Pandaria optimisticly going in "early 2013" ;) :D
Ultimately, as Jay Wilson said some time ago:
Our job isn't just to put out a game, it's to release the next Diablo game. No one will remember if the game is late, only if it's great.
So I'll wait, and have fun with the rage comments of the "angry fans". : D