In a fascinating and wide-ranging interview with Geoff Boucher in the Los Angeles Times, Christopher Nolan, director of Batman Begins and The Dark Knight, provided what he called a “suitably slippery answer” when questioned about helming a third Batman film. Nolan cited two concerns, the most important of which was finding “a story that’s going to keep me emotionally invested for the couple of years that it will take to make another one.”
Nolan’s other more superficial worry was expressed in a question: “How many good third movies in a franchise can people name?” Nolan answered this concern by noting that “in taking on the second one, we had the challenge of trying to make a great second movie, and there haven't been too many of those either.”
Certainly there will be enormous financial incentives to make a third Batman film as The Dark Knight has currently amassed some $991,347,433 in worldwide box office sales. But in spite of what must be extreme pressure from Warner Bros., which wants to use a sequel to The Dark Knight as the lynchpin for its entire slate of DC Comics-based movies, Nolan appears to be holding out until he can come up with the right narrative, telling the Times, “It’s all about the story really. If the story is there, everything is possible.”