Batman/Bruce Wayne. I think he would give a great performance. You already know from his personality he can play the billionaire playboy. He's in great shape and known to action adventure films from Mission Impossible days. As long as he's not allowed to have influence on the script at all, everything should be ok. He has the acting chops. If you've seen him in Last Samurai his portrayal of a tortured character is exactly how Wayne should be approached. I can also see him as a great Batman throwing himself into the role. Forget all his antics outside of his work. Just don't let him make any decisions on the movie and just hire him as an actor.
Pros:
-Star power
-Good actor
-Bat-***** crazy
Cons:
-50 years old
-Really short
-Bat-***** crazy
I gotta say no