The ending of Christopher Nolan's The Dark Knight Rises sparked a lot of discussion and debate among fanboys and fangirls. It even sparked rumors that Joseph Gordon-Levitt would end up playing the new Batman in future films. Most recently there was a big rumor that he would be playing Batman in Justice League, which his reps quickly shot down.
I liked the open natured ending of Nolan's film, it left me with a feeling of hope that the Gotham City Nolan created will always be protected. Sure, I thought it would be cool to see the franchise go on with Gordon-Levitt taking the lead, but I never really expected it to happen because Nolan said over and over again that this would be his last film, and that it would close his story.
The director recently sat down for an interview with Film Comment, and during that interview he explained his open-ended finish to the film saying,
For me, The Dark Knight Rises is specifically and definitely the end of the Batman story as I wanted to tell it, and the open-ended nature of the film is simply a very important thematic idea that we wanted to get into the movie, which is that Batman is a symbol. He can be anybody, and that was very important to us. Not every Batman fan will necessarily agree with that interpretation of the philosophy of the character, but for me it all comes back to the scene between Bruce Wayne and Alfred in the private jet in Batman Begins, where the only way that I could find to make a credible characterization of a guy transforming himself into Batman is if it was as a necessary symbol, and he saw himself as a catalyst for change and therefore it was a temporary process, maybe a five-year plan that would be enforced for symbolically encouraging the good of Gotham to take back their city. To me, for that mission to succeed, it has to end, so this is the ending for me, and as I say, the open-ended elements are all to do with the thematic idea that Batman was not important as a man, he’s more than that. He’s a symbol, and the symbol lives on.
That pretty much sums it up. I don't think Warner Bros. is going to tinker around with Nolan's Batman universe anymore. It's safe to say that that story is closed, and that when the studio does bring back Batman, it's going to be another reimagining of the character. I don't see Nolan's universe spilling into any of Warner Bros. future DC superhero movies. I'm looking forward to finding out what exactly they're planning for the future of the Batman franchise.