Is Cataclysm are now the final expansion?

Tier 13 must be the last tier in Cataclysm, but is it over for the game? Is Cataclysm are the final expansion of the game, or are you still making the next expansion with new classes and races, and expand the level cap to 90 or something?

If the Cataclysm is the final expansion of the game, then are you going to start a new World of Warcraft game called "World of Warcraft 2", or are you done yet?