I used to think that ROTS was just filled with too much stuff. It seemed that both episode's I and II were both mostly just filler and then III had the bulk of the story. I never throught that someone's fall from grace could be covered in one movie, that is until 2008 rolled around and I saw Christopher Nolan's THE DARK KNIGHT. Now that I've witnessed a person believably go from good to bad I hate the prequels even more.
Here's what we as the viewer got.
1999 - a disney-esque kidflick with acting that is subpar to say the least.
2002 - a who-dunnit that never actually answers the big underlying question. (sifo-dyas??) (Kamino file??)
2005 - The movie George had been waiting to make but never actually sat down to hash out how Anakin would go to the darkside until just about the day of shooting. (and then redid in post)
I can only dream of what these movies could have been with just about anyone else writing and directing.