I dunno how valuable my opinion is, as I was never a Star Wars aficionado per se... rather, a casual viewer of the movies. Don't get me wrong, I loved Vader and Yoda and Chewie, and I thought the first three movies were awesome when I watched them as a child.
That all being said, I find I can't rate Star Wars, Empire, and Jedi separately... because I view the three movies as one big story. Of course, many of you will say: 'But, you can rate each of the movies on their own respective strengths and flaws'... and yeahh, I could, but to me, it would feel like rating a good music album, and then taking the first 4 songs on it and rate that part, then take the next 4, etc.
The prequels, however, I do have something of an opinion on, separately from each other. I harbour a controversial love for Phantom Menace... I've seen it in the cinema, at the age of 12, and loved it. I haven't seen it since. At that time, I watched it the same way I had watched the original Star Wars movies: as a fairy tale in space, pure entertainment. It succeeded, for me, on that front.
I saw Clones much later, years after its theatrical release, on a TV channel somewhere. I personally thought it was very weak. What bothered me most was the Padme/Anakin romance, which felt forced and clichéd to me.
Sith I really liked, but something was missing from it when compared to Empire of even Jedi. I think, what was wrong with it, was that Sith was one long chain of action scenes. It was a LOT of fighting. Mind you, there were many awesome fights in it, like Obi Wan vs. Grievous, or Obi Wan vs Anakin, but what was different in the original films, was that you had breathing time in-between the action. An important thing of note is perhaps that the original three movies introduced stuff you as a moviegoer had no previous clue about, such as the Sand People, the X-Wings and Tie Fighters, Jabba, Chewie, the Droids.. then later, stuff like Yoda on Dagobah, planet Hoth with Tauntauns and the Wampa, later still the Ewoks, love 'em or hate 'em.
With Sith, I kind of had the feeling that everything had been established. There was some new stuff but not much. There were characters walking around who weren't named, and whose identity you would only know if you'd (later) play a video game, or read a novel, or a comic book, or watch one of the animated versions, and I'd prefer they deal with that in the movie itself. But everything had been established, even though this movie technically takes place BEFORE Star Wars. So, scenes like Yoda meeting Chewie and the Wookies feel a lot like 'Oh, you already know these characters, we just throw them in as a shout-out'. There wasn't much exploring of NEW concepts in especially Clones and Sith. And especially Sith, to me, felt like it was designed to be a bridge between Phantom/Clones and the original trilogy. Wrapping up the loose ends went way too quickly to my tastes, and frankly, I thought Anakin's fall to the dark side felt very, very artificial and contrived.
I find myself in the camp of people who say that Anakin Skywalker in the prequels doesn't come across as the 'great noble hero who tragically fell into the temptation of the dark side', but rather as a selfish, arrogant, whining loser.
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clarity of thought before rashness of action