I've long had this idea that Bizarro, as a playable character, should be odd, and that his control scheme should be the opposite of everyone else's.
Using the PS3 controller as an example, players would move Bizarro with the four buttons (triangle, square, circle and X), and use the control pad for his regular attacks.
Special moves/finishers that require to press down + forward, would instead be done by pressing square or circle (depending on which side of the screen you're on) + X. Or, to make it just a little easier, you'd press square + X when on the right side of the screen, and circle + triangle when on the left.
Alternately, there could just be an optional Bizarro mode for players who like a challenge, and that mode would be playable as everyone, not just Bizarro.
What do you think?