First Class WAS NEVER intended to be a reboot and it has been confirmed from Singer time and time again, its a prequel. That said, they could simply reboot it and start the new series with Bruce already as BATMAN. That is quite possible.
Also, if this trilogy is supposed to be somewhat grounded in our reality, as Nolan has tried to pull off, doesn't it make perfect sense for Batman to die in action? I mean, in real life, a crime fighter dressed as a bat can't keep this up forever. He constantly takes on multiple thugs at a time with guns, while he has nothing, but his bare fists. As Badass as that is, in the real world, the chances of a Batman type vigilante dying at an early age in battle is about 100 to 1.