True, but not for Batman. He could have spent his whole life doing that if he wanted to.
That is true, you're comparing casting to story and subplots, and as a whole the TDK trilogy is great, no denying it. It was well received and generally loved by fans and critics alike, if you don't like it, then so be it. Let's get back on topic and listen to the thousands of nerds cry about Affleck being cast as the Caped Crusader.