I didn't see the Dark Knight Returns or whatever and I know it had Bane, but I don't think it had Azrael. That was a key point of the series - Batman being replaced by another Batman. It demonstrates the unrivaled mental fortitude and power of Bruce Wayne that he can walk that razor's edge. Having someone else in his shoes, seeing them try and fail to be him, makes you appreciate Batman even the more.

JPV could also be a very tragic character if done right.