Sound and Fury
I might as well start by linking to Anthony Lane's review of Star Wars Episode III (published in the New Yorker), because it's wittier than anything that I'm going to write.
That said, I don't completely agree with everything he wrote. Much of the charm in the original trilogy came from some of the less septic locations: the cantina from A New Hope, Jabba's palace, etc. In fact, the first scene in the cantina was one of the most amazing displays of effects of its time, and did a lot to convince people that the movie coming up was going to be cool. However, the more recent movies have completely lost that charm. Even in the one visit to a "seedy" location in the more recent trilogy felt more like a bone thrown to fans of those moments in the original series than a serious attempt to explore the underside of Coruscant.
My real problem with Episode III is that George Lucas is about as subtle as the average jackhammer. Lane comments on his tendency to pick overly dramatic locations — the lava planet is a prime example — for the action, but it goes far beyond that. One example that caught my eye is that the Jedi characters all have full-on face lighting (except for one painfully out-of-place noir-like scene), while Annakin has half his face shadowed for the entire movie. Used once or twice, the contrast would have been interesting, but Lucas drives it in and breaks it off. It spreads to costuming: while rest of the Jedi wear brown and white, Annakin wears black. Symbolism is good and all, but when it's that obvious, and within something that pretends to be a religious order, it would have been nice if Lucas had given us a word of explanation.
The characterization is equally black and white, and that really sinks the trilogy. Palpatine is so overtly creepy that it's difficult to see how anyone could trust him, let alone an entire galaxy. Meanwhile, the Jedi are portrayed as so ascetic it's difficult to really believe that they're human — or anything like it. Annakin's range of emotions consists of wooden and screaming, and his love interest manages to extend that range only to crying. In the end, it's difficult to care much about Annakin's betrayal when his tempter has been overtly evil from the beginning of the trilogy, the characters he betrays are generally unsympathetic, and Annakin himself is completely unappealing.
The general consensus has been that Episode III is better than the two that preceded it. Unfortunately, the improvement doesn't extend beyond the special effects; George Lucas can still only see the world in one of two extremes and that gets very boring very quickly.
