But why would they do that? Even if they want a younger one like they have been doing with the rest, its the same cause Wolverine is practicaly inmortal.
Well think about how much he has to go through to buff up for the role of Wolverine. He has to stay in great shape for an extended period of time to be Wolverine. And he might be getting tired of the role because he's done it for so long. They have to recast him eventually.
http://www.imdb.com/title/tt0016629/?ref_=fn_al_tt_3
http://www.imdb.com/title/tt0020668/?ref_=fn_al_tt_2
http://www.imdb.com/title/tt0035665/?ref_=fn_al_tt_9
There were at least 3 batmen before Keaton. "The Bat" and "The Bat Whispers", both by Roland West, were the direct inspiration for Bob Kane's Batman, and the third is an old serial based on the character.