As for effects, I think they're largely overrated. I still think the effects in Star Wars hold up better than the ones in Episodes I, II, or III. The use of CG animation only expands your choices, it doesn't mean you'll make good ones. The earlier movies didn't rely on entire worlds being created in the background, so they were forced to focus on the characters. There were very few wide shots that weren't of something the average 1977 human could recognize* - Tatooine=Sahara Desert; Hoth=Alaska. No big whoop, I've seen that in pictures before. Now show me what the people are doing, how they're feeling. Since the technology's gotten better, it's become less about characters and more about cool planets and improbable aliens. Wonder why the performances by respected actors are so bad? Treakly dialogue is part of it, but filming every scene in front of a green screen makes it difficult for even good lines to be delivered well. There's no set, no scene, just a wharehouse and a bunch of computers to add everything later. The actors are uninvolved and so, mirabile dictu, is the audience.
Lucas commits many of the same sins in ...Sith, but he manages to remember he's telling a story about people first, planets and politics second. It's far from perfect, but it's good enough to end with.
*Exception: wide shots of Death Stars. Very cool, but not exactly FX wonders.