That's technically a sequel and Nolan doesn't want that.
As I said, WB want to re-imagine everything about Nolan's films into a soft reboot. Changing things slightly, but still keeping them familiar to the past, without be connected.
That means to re-imagine Nolan's level of realism, changing it to a degree to allow the obscure villains. Toning it down, but sill making it plausible for us to accept in our world.
Re-imagine his look of Gotham, again keeping it similar, but still being different.
Re-imagine the Tumbler (Batmobile), making it closer to the comics.
Even re-imagine Batman and other characters. Trying to make them different, but still keeping them similar to Nolan's vision.