most seem to be suggesting hardware advancements. what about achievements? heck they are used in video games, and even the workplace and school now (gamification), why not pinball. It would be cool to have other objectives besides points, some small examples of this being used today is:
Getting Acheivements could be used to unlock extra Animations, music, or even modes on the machine.
They could be straighforward like "Beat the Wizard Mode", or obscure like "Beat Mode with only the Left Flipper" or "Make Shots Sequentially from Left to Right".