The next expansion is known as the "Black Empire", which is about the corrosion of Azeroth's world soul and the control of "void". It will have old area remodeling like "cataclysm", and there will be a lot of old god things.
The main villain of the expansion is "azshara" and "n'zoth", but the ultimate boss will be to release the soul of Azeroth from "void".
The expansion hero will be "Wrathion" and "Magni".
There is a new race called elite race. They are the "dragonsworn" of Wrathion. They start at level 108 and can be any class. They have the ability to switch between half dragon form and any race of its faction. which race you choose during the character creation, but can not be changed. you start as your normal game, but then Wrathion changes you.
can not be hero class or monk but can be any other class that the "regular" race they pick can play as