Why? His game bombed critically and commercially, and having been at the event last year, his schtick didn't go over well with the audience.
EDIT: Alright, maybe his game did alright commercially but all of the professional takes I heard on it were underwhelming. The Game Informer guys especially seemed really unenthusiastic. And honestly, being at the show last year and sitting relatively close to him, his act bombed. People seemed more annoyed than anything.