I like the idea of Nolan trying to wrap things up naturally with the third movie and doing it in a way where it would be difficult for others to continue the series in a way that taints what he's done, but I really hope he doesn't go the route of killing off Batman.
I think that would be such a cheap, lazy way of trying to bring closure to a series, and one of the things that pissed me off about the third X-Men movie. It's like the philosophy was: Let's kill off a bunch of main characters and take away the powers of some of the other ones so this definitely feels like the last one and anyone wanting to make a sequel has a hell of a lot of work ahead of them to undo all the damage we did! Pretty stupid approach to capping off a series, in my opinion.
And Nolan is definitely aware of the threequel curse. He talked about it to explain why he was reluctant to do the third movie. If anyone can break that curse, though, I have faith that Nolan is the man to pull it off. But yeah, he needs to realize that letting Bale do his stupid Batman voice was one of the worst choices he made in the series. One of the few mistakes he's made, but still a big one.