The liberty I'm taking with his statement (which are in depth and undoctored about the net) is that he is wanting to make sure its as artistically important to the character as TDK was for the character(s). I see Nolan as much more an artist in his field then I do say Michael Bay. I think if Nolan took a year and couldn't come up with an idea that pleased him he would pass on doing a 3rd Batman. Warners on the other hand would just get Paul Anderson or some other step down in talent director and make the movie.
There will be another Batman, count on it.