Hah, yeah - that's kind of what I am saying.
He seems to have had a surplas of names, characters, locations and - at best - situations and scenarios, knocking around pretty much since day one. But the actual story that all these things hang on... it's almost as if Lucas thought that the narrative was also in there buried among his notes, and if he just went back and kept mining these concepts the story would work.
While this worked for episodes five and six, where the characters were always moving somewhere new, the flaws of this way of working were exposed when trying to deal with a backstory we already know the outcome of.
I mean, I'm in the camp that loves ROTJ, but I can see its flaws. How all it boils down to is, first act: Nonsensical recue plot simply to return one of our heroes to the fray and, remainder of the film: Rehash of the Death Star attack from the first movie with the unused primitive hairy tribe idea grafted back in - all seasoned with a bit of "certain point of view" backtracking.
It is clear the ideas were being spread thin by that point, but in this case the character arcs could be brought to some kind of satisfying resolution, because he had the freedom to make it up as he went along. The saving grace was that the first two films were good enough to make us care about these characters and what happened to them in ROTJ.
With the prequels, we knew where everything was headed, so that freedom was gone.