Atriox, because he is so powerful It's one of those if you can't beat them join them" things but I just don't like playing him because he is so damn good. Not only does he have some of the best Offensive and defensive leader powers in the game his leader is also a one man army.
Jerome but only because he is already a hero for cutter so it makes it strange when I see two different jeromes on the same team or fighting each other, also his rocket gun just doesnt fit his character. I would of really liked if he started with a halo assault rifle or shotgun. His last upgrade could of been the rocket gun if he needed it for late game damage.