An artist owes **** all to a fanbase. I'm sorry but i dont come from that line of thinking at all. You either enjoy the output, or you don't. It doesn't matter if it's a hundreds of millions of dollars in budget, a massively known band, a small indie film, or an unknown broke band. The artist owes nothing.
If you make movies for the fanbase you're a bloody ******. Your art isn't art anymore it's just a product. But those kind of movies would indeed need to do things according to what their fans want. Like an entertainment/pop group. This isn't the same thing because Nolan wouldn't have done this movie if he didn't have a story to tell. Let the production companies, etc worry about their fanbase and how they're going to sell it to them. Nolans job is to not worry about fans or anybody else and just write and direct the movie he wants to make. A big Batman movie or something like Memento...it's all the same thing.
The fans don't own Batman, nobody does. They're entitled to nothing. If somebody wants to come in and butcher the idea of Batman (ill say that its been done before but i mean in the future) and do it assbackwards, and show the Batman just once the entire movie. Or use the Joker in some weird way, they can..and they dont owe the fans **** all. You either buy it or you dont. The artist can interpret it however they please.