Bale's good, but I'm not sure if he's great. He's shown that he's really skilled at picking collaborators, and taking roles that suit his strengths, but amongst his notable roles, I don't see a whole lot of range, so far.
Nolan's a pretty good director. I actually think that taking Batman movies is kind of slumming it for him, but if he has success with more than one of these, he could probably get whatever he wants bankrolled, so overall I suppose it's a smart strategy.