To me, the P3 is where the only true innovation in pinball is occurring. The ball tracking technology essentially turns the middle of the playfield into a giant iPad, using the ball as the stylus instead of your finger.
I can imagine endless possibilites like animated, moving arrows showing you where to shoot, or a "covered" playfield where you have to use the ball to wipe away the "sand" to discover archaeological artifacts, or a completely random moving target you've got to hit in under 5 seconds.
Yes, the lower playfield will be the same, but the upper can be anything from a simple field of pop bumpers, to a swarm of interconnected ramps and forms. If you look at how the slings are cantilevered off the apron, there's nothing saying you couldn't bolt an upper playfield feature's support onto a side of the lower playfield.
Combine that modular flexibility with the endless variation from the software/rules/art side, and you've got the ability to have a ton of variety in one package.
I for one can't wait!
Later,
EV