According to sources at MMO-Champion there's a lot of new information about the new suspected expansion "Cataclysm". Some of the rumors include complete revamps of all of Azeroth to allow flying, The Barrens being split down the middle by some major event that also cracks the Greymane Wall. The Goblins have been enslaved by Deathwing and a group of them have splintered off and joined the Horde while the residents of Gilneas transformed by the Worgen curse permantly have joined the Alliance. Theory has it the expansion will be slightly smaller than a traditional expansion and the level cap may only turn out to be level 85 with older dungeons and raids might be brought back to the forefront and redone for level purposes. There's a lot more info located on the MMO-Champion website.