While I don't consider it to be a fatal flaw, I think the real problem started with Empire Strikes Back. Prior to the development of Empire Strikes Back, Star Wars was looking to be a much more light hearted series. I get the feeling it would have been a lot more like Indiana Jones were each movie was an all new adventure for the Star Warriors. GL even talked about having other filmmakers come in an take a stab at some continuing adventures with his characters. I think it would have played out like an ongoing comic book with each movie being a new story arc.

Instead, Empire comes along and makes Darth Vader Luke's father and establishes that Star Wars was episode 4, there are now 3 prequels about Anakin, and at least one more sequel since Empire ended on a cliffhanger. Empire may have been great, but it marked the beginning of the interconnected 6 part melodrama that we ended up with instead of the continuing adventures of Luke Skywalker and the Star Warriors that we could have gotten. It could have been better, but then again, it could have been worse.

While I don't think it's fair to compare Empire to the prequels, as far as I'm concerned, it was the same line of thought that produced both.