darklordoftech said:
Kurtz once said that Palpatine wasn't supposed to appear until IX, but then GL condensed V-IX into V-VI. I would have loved a longer arc from ANH to Palpatine's death.
Unfortunately, Lucas had nowhere enough imagination to generate interesting new adventures over any extended period, so he just wrapped and twisted the limited set of ideas from the project's inception into itself.
He was furthermore too controlling to open up to new writers and other talent, so he had no choice but to just end it.
To sustain six movies of consistently fresh plot would have required a steady flow of imaginative infusion. It proved impossible.