IMHO, I feel "Smallville" does a better job of taking a "good" Lex Luthor and making him "evil" than RotS did with Anikin/Vader. I still wonder why it took everyone by surprise when The Big Secret was revealed. (I figured it out in Phantom Menace... of course, I knew what the future held from Eps IV-VI
)
You would think that Jedi Knights would be experts at observation, but they seem, on the whole, rather clueless. A Bene Gesserit witch from "Dune" would have had the Jedi (or the Sith, for that matter) naked in the desert collecting spice and saying, "Thank you ma'am, may we have another?"
So, after all that, I must rank "Revenge of the Sith" as the best of the Prequeal Trilogy, and "Empire Strikes Back" as the best of the second (oriiginal) Trilogy. "ESB" is the best of all the Star Wars movies, mostly due to the interaction between Leia and Hans.