Both the director and the Dark Knight himself could use a new challenge.
After this Friday's The Dark Knight Rises, director Christopher Nolan will stop making Batman moves—and that's a good thing. That's not because his have been bad films. Quite the opposite. The boldness of Nolan's storytelling, the seriousness and conscientiousness with which he addressed comic books as a form, and the degree to which he interwove comics conventions with cinematic ones, showed the world just how great comic-book movies could be. Without delving into too many spoiler-y particulars, Nolan has concluded his Batman trilogy on a fairly definitive note, and has said all he has to say as a writer and filmmaker about Batman as a character and (even more importantly) as a symbol. This is why even though both Batman Begins and The Dark Knight were enormously successful with audiences and critics, and The Dark Knight Rises is almost certainly poised to continue that trend, it's time for Nolan to tackle a new challenge and for Batman to be re-imagined yet again.
Nolan, starting with his second feature, 2000's Memento, has delivered a string of intelligent pop movies that are meticulously constructed, have a wide sweep, and are morally and formally complex. He's said that he considers Stanley Kubrick, Ridley Scott, and Michael Mann to be his influences, and you can see the traits he shares with those directors: a flair for making bleakness engaging rather than ponderous, an interest in haunted, driven protagonists, and particularly in Kubrick's case, a knack for adaptation. Nolan's films deal heavily with memory, perception, and the knotty, amorphous definitions of right and wrong; they're not terribly profound in the way they go about exploring these subjects, but their subjects are worthy ones that aren't tackled all that often in mainstream (increasingly expensive) films.