Theme and pinball have nothing to do with each other. Themes are a necessary evil in order to sell machines. I accepted a long time ago that a pinball theme means nothing if the design is not there.
If you don't mind paying 5 grand for something that is poorly designed and you are ok with the theme only, good on you. . You play pinball, not the theme. Theme is more artistic and it can be very poorly implemented. I actually feel that the most recent Stern Star Trek theme was a poor effort. However, the game is fantastic and one of Stern's best. Reinterates the fact that theme means nothing.
I love Disney's classic Tron but the theme had a completely different feel when Stern did it. They had to comply with the liscence. I would not own Tron pinball if it sucked and happened to just be a "Tron theme". That makes no sense to someone that just wants to play a good game of pinball with friends.
Now, to me, theme can enhance a good pin and make it great. Case in point would be TAF, TZ, or Metallica. But theme should never be the starting point, if you are a true fan of pinball.