How will Warner Bros. follow Christopher Nolan's epic Dark Knight trilogy? The challenge that Warner Bros. will likely face is that fans might reject another origin reboot as being too soon, so it might be better for Warner Bros. to go a different route.
According to Batman-On-Film, they've heard rumors that the next Batman movie reboot could be an adaptation of the Batman Beyond animated TV series. If Warner Bros. goes the Batman Beyond route with the Batman reboot, then it would be set completely outside Christopher Nolan's Dark Knight universe.
Of course, Warner Bros. is planning a Justice League movie, so why would they focus on a future Batman in a Batman reboot? Well, according to Batman-On-Film, Batman Beyond could still exist in the new Justice League universe. There could be a present version of Bruce Wayne in the Justice League movies, and the same Bruce Wayne could be elderly in the Batman Beyond movies.
In the Batman Beyond animated series, an older Bruce Wayne trains Terry McGinnis to be the new Batman in a futuristic Gotham City. It would be an interesting take on the Batman franchise, which might help Warner Bros. avoid criticism for doing something too similar to the Dark Knight too soon.