Who says they have to move away from the Nolan universe at all?
The vast majority of the audience for these last 3 movies probably does not even recognize the name Chris Nolan. If you give them another movie that looks & sounds & feels like another Nolan movie, then they will buy tickets like it's another Nolan movie. A new batch of actors will be required as well as a new director/writer/etc. But that does not mean they are obligated to change the rest of the look & feel of the Batman universe too.
It would be more creative to take a whole new direction with a reboot but that doesn't mean they will do that. Movie studios are not in the business of being creative. If they think the most near-term profit lies in cloning Nolan's style one more time, then that is what they will probably do.
The vast majority of the audience for these last 3 movies probably does not even recognize the name Chris Nolan. If you give them another movie that looks & sounds & feels like another Nolan movie, then they will buy tickets like it's another Nolan movie. A new batch of actors will be required as well as a new director/writer/etc. But that does not mean they are obligated to change the rest of the look & feel of the Batman universe too.
It would be more creative to take a whole new direction with a reboot but that doesn't mean they will do that. Movie studios are not in the business of being creative. If they think the most near-term profit lies in cloning Nolan's style one more time, then that is what they will probably do.