The prequels commit perhaps the worst sin a movie can commit: being boring. I can forgive a lot in a movie if it’s even just a little bit interesting or engaging, but the prequels* are just dull.
*It’s been years since I’ve tried to watch RotS, but I doubt it’s much better.
I take that back, the worst thing a movie can do is be morally repugnant, like Nazi propaganda films or something. Being boring is probably the second worst thing.