There is a part in ROTS, right after Padme lands her ship on Mustafar, when the movie stops for a few seconds to hang on a shot of her resting her head on her hand, gazing out the window lost in contemplation of what she's about to face, and starting to cry, while a somber rendition of Anakin and Padme's love theme plays in the soundtrack. For a fleeting moment, I'm transported to a different dimension where the rest of the prequel trilogy around that scene disappears and is replaced with what it should have been.
The problem is that the prequels fall so short of their potential that, paradoxically, the good things about them just serve to make them even harder to stomach.