I've been thinking some more about this and, personally, if I were George Lucas, there are two major things I'd have done differently.
Firstly, I would have kept the first movie's title simply as STAR WARS. no added episode number later, the sequels are simply called THE EMPIRE STRIKES BACK and RETURN OF THE JEDI.
Secondly, I would have told the stories of the prequels with a trilogy of books... That way, you get to know how and why Anakin Skywalker turned to the dark side, you hear all about The Clone Wars, and you get to picture the characters however you want to. There aren't so many disappointments when the actors chosen don't match the images we've had in our heads for the characters.
AND... For any newbies, or those who only watch the films... There are NO SPOILERS!!! :)
This solves the problem in my mind... I'll probably get blasted for saying it, but there you go. If other films had to be made they could've been about another group of characters. Stand alone stories, completely unrelated to the STAR WARS TRILOGY...
Just imagine the front covers of those books... Anakin and Obi-Wan shown as younger versions of Alec Guinness and Sebastian Shaw!!
I think if Lucas had done this, instead of making them movies, he could have stayed truer to the original ideas he had and, therefore, he would have been able to tell a far better story, it could have been a true epic and even become one of the great sci-fi book series of all time!!!
I'me getting pretty overexcited thinking about this here... Lol
I'd have loved to see this though!!! I'd love to hear what you guys think... :)