In the interview, Nolan let's a few tidbits fly. In the world he's creating for Superman, there are no other heroes.
“A lot of people have approached Superman in a lot of different ways. I only know the way that has worked for us that’s what I know how to do,” Nolan said, emphasizing the idea that Batman exists in a world where he is the only superhero and a similar approach to the Man of Steel would assure the integrity needed for the film. “Each serves to the internal logic of the story. They have nothing to do with each other.”
He won't confirm that the title of the film will be The Man of Steel as rumors had suggested, and his wife, producer Emma Thomas, flat out states that she has no idea where that came from. No information is shed on who will direct Superman, but Nolan states that he wants to employ the same "big name" casting style from the original films.
In regards to Batman 3, Nolan keeps the details at a bare minimum. His brother, Jonathan Nolan, is scripting the film with the idea that this will be the end to these characters' story.
“Without getting into specifics, the key thing that makes the third film an great possibility for us is that we want to finish our story,” he said. “And in viewing it as the finishing of a story rather than infinitely blowing up the balloon and expanding the story.”
Nobody believes for a second that this will be the final Batman film. It might be the last one the Nolans are involved in, though. Also, just because they aren't writing Superman and Batman to be in the same universe doesn't mean at all that they aren't. It only means that the stories are being written with one hero in mind, so conceivably both characters could still be involved in any future Justice League projects that came down the line.
The interview has tons more insight into Christopher Nolan's mindset. You can read the full text here.
