It makes sense since she hates her People (more like former People) and it sets up the Raid with her as the last Boss. I just don't believe that the Horde burned Teldrassil, there has to be some kind of swerve
I love seeing all these theories, but c'mon, the answer has been fairly obvious for a while.
Teldrassil is on fire, the world is in chaos. Which class uses chaos and fire magic and has an aptly named talent specialization for reaping destruction?