Annie is the best assassin in the game.
All she has to do is click on anyone with less than 2000 health and her Q will instantly delete them. Not only that but there is absolutely ZERO counter play to it. All you can do is run away from her.
I don't know if this is a problem or not but it sure as hell feels like it when she can one shot an entire team when everyone is at level 18 and all have full build OH and did i mention that this all while only having 400 AP? Yeah, the rest is tank stats. So bullshit.
delivers on the theme of assassination better than 
and jumps at your face like some drunken brozerker 
Charge your opponent head on and kill them.