I'm still trying to wrap my mind around all the things wrong with "Sith" (aside from the word "Sith.") I remembered reading an essay by a total fan boy a few years back in which he lamented that the third film would ruin the movies that came first, and he detailed how Lucas could possibly fix it. I found the piece again today, called Star Wars: The Prelude Problem and I don't know if the guy went back and re-wrote it, but if it was indeed written in 2000, then the Force is strong with this one, because he was able to predict a lot of the moments that actually made it into Episode III (for better or worse). His basic idea is pretty good (it's an attempt to maintain the "I am you father" shock moment of "Empire") but I kind of disagree that big reveal is necessarily lessened with the existence of "Sith." Instead of it being a shock for us, the audience, I believe we are instead asked to identify with Luke, and have an "Uh-oh! He's about to find out the truth. That's gotta be tough" moment when those "I. Am your father..." words are spoken.
Oh my god. When did I turn into such a raving "Star Wars" geek? This is freaking me out. But at least I can spell a little better than the person who wrote the above-linked article.