I need to know about Batman and movies

Last night Julie ended up catching 2/3 of Pretty Woman, and then came and told me how much she disliked the plot. And then we discussed it, and the most fun solution to improving it was to make the male millionaire a young Bruce Wayne. Because if you're going to make a silly white knight story in which a woman is saved from a terribly life, you might as well have her saved by Batman (and have him learn that he could do positive things for society with his money, as well as beating up thugs).

Which left me wondering - what other movies would be improved by replacing one of the characters with Batman?

And what, if any, movies would be made much worse if you made the male character Batman?