My initial reaction:
But now that I think about it... I think he can pull this off. This will be a different Batman than we have seen before.. they are jumping right into a wiser more experienced Batman, almost a tutor for Superman.
He definitely has the look, will need to add the muscle. Bale wasn't even that great of a Batman, it wasn't until the third movie that I was really sold on him as the Bat. Afleck has come a long way and I will give him a legit shot before passing judgement. Now get Chris Pine as GL pleeeeaasseeee.