It’s out. The new World of Warcraft Expansion would be named Cataclysm.
There will be some big changes as well as new races. The Goblins will join Horde forces, Worgen to the Alliance. Some of the class limitations will be lifted too, so we’d may see some human druids or human hunters, Dwarf mages etc.
Level Cap will only be raised to Level 85 this time, to keep enough space for the future and not get to level 100 so fast.
As for the continent, there won’t be any new continent with the Cataclysm Expansion. Instead, old Azeroth will be revamped by using the Phasing Engine (like it was introduced with the Wrath of the Lich King. We remember, where the zone changes over time, like the Death Knight start area). Flying will also be possible in Azeroth as well as some of the old zones and dungeons to be revamped.
Deathwing will reappear again in Cataclysm and play a major role in the story. He succeeded in creating a new generation of supreme Dragonflights and going to unleash them upon the World of Warcraft.
For the first time Azshara herself will appear in this Expansion and playing another major role in the story on the side of Deathwing. The long missed Queen, even forgotten and thought dead by her own kin, will rise from the depths of the Maelstorm and threatening the live on the Planet Azeroth.
After all it’s still unknown who may be the true end boss of this expansion. But speculations are that it may be one of the remaining Old Gods (after C’Thun and Yogg-Saron, only 3 are left).
Malfurion will return back to Azeroth and Thrall becoming the new Guardian of the Tirisfal, giving up his position as the Leader of the Horde. Garrosh Hellscream will take his place as the new Leader of the Horde.