Are you saying that 1-3 shouldn't exist?
No, I'm saying that you know so precious, precious little about how our characters became relevant to the overall arc, and because you know so very, very little about how we got to where we are, that the choices Lucas could have made were virtually unlimited.
There's no reason 1-3 had to have ANYTHING to do with Luke Skywalker, Obi Wan, or any of the rest of them in anything but the most glancing of ways. It would have been better, in fact. Luke Skywalker matters because he was Everyman. Empire works because holy shit he's Darth Vader's kid. Jedi starts to come apart because it's all in the family... and then the first three basically say "the Skywalkers have always been at the middle of the goddamn universe and everyone else is a prole."
Star Wars 1-3 could have had Emperor Palpatine's rise as a back story, Darth Vader as a glancing afterthought and SOMETHING COMPLETELY DIFFERENT at the core. But that would require imagination, which George Lucas kind of ran out of in '83.