Clooney and Kilmer were doomed in bad films. I think both could have done better than Bale's Batman in the Nolan films. I'm obviously counting 90s Kilmer, not the overweight one of the aughts.
When I think about all the things that made Batman Forever bad...Kilmer doesn't cross my mind. He wasn't a bad Batman, and his Wayne wasn't bad either. Meanwhile Clooney was quite an asshole as Batman, but then again I often view Batman as an asshole. I'm not sure any Wayne displayed more swag than Clooney's either...because, well, Clooney.