Director Quentin Tarantino recently did an interview with The Playlist where he talked about a whole slew of things including his favorite films, and an erstwhile defense of the Lone Ranger, but perhaps most interesting is that he said that "Batman is not a very interesting character."
Tarantino was also asked for his thoughts on Ben Affleck playing Batman in the "Man of Steel" sequel. "I have to admit that I don't really have an opinion," he said. "Why? Because Batman is not a very interesting character. For any actor. There is simply not much to play. I think Michael Keaton did it the best, and I wish good luck to Ben Affleck. But, you know who would have made a great Batman? Alec Baldwin in the '80s." source
Now, throughout the years, there had been a whole slew of Batman TV shows and movies with numerous storylines and a whole bunch of actors playing the superhero. And so for someone to say that Bruce Wayne just isn't interesting enough of a character, well, I might have to hear an explanation on that.
Unfortunately, that's as far as Tarantino went so I can't really tell what he means. We do know that he likes Michael Keaton's Batman and thinks Alec Baldwin would've made a great Dark Knight 20 years ago, and wishes Ben Affleck all the luck for playing the caped crusader in the Man of Steel sequel.