I’d say the ideas behind the prequels are substance. Too bad Lucas’ ego didn’t allow him to pass them along to someone with actual talent to develop and execute competently.
From what I’ve heard, Lucas didn’t want to direct. He wanted to hand the project over to someone else with him producing, like in Empire and Jedi, but the studio insisted on making it “his project”. What they didn’t realize was the OT everyone fell in love with wasn’t what George had wanted in the first place, and it was only with his limitations and other input that such a balance between creative substance and inspiring narrative could be accomplished.