I think the difference is Lucas had ideas, he didn't write the scripts first, and things shifted as it went. But there were ideas there for him to go from. Compared to zero plans, no idea for the direction things would go. And then play choose your own adventure with the next director. I think that's the difference. No one starts a novel, movie, a video game... And has it figured out 100% before they start. That's not how it generally works. Even a basic framework will guide you through the process. And it should change, it should evolve, that's just the creative process. Lucas started out with ideas. He had an idea in his head of how he wanted it to go. Disney had nothing. The only thing they planned was to move away from the OT characters.