I can’t think of a single prequel that changed the original work in a positively-received way.

That’s something to keep in mind. Prequels are very difficult to pull off in a way that enhances original story rather than undermining it. They’re usually more likely to work if they’re not a “direct” prequel but are instead just a different story set further back in the timeline.

The prequels built themselves around the anticipation of Anakin becoming Vader (you can even hear Vader breathing at the end of TPM’s credits), but didn’t do enough of the character work to make that transformation feel gradual or earned. And the fact that Lucas chose to hinge the trilogy on Anakin’s arc means it really needed to work.

TPM is an especially fascinating movie to me because it’s a rare case of a movie that may have benefitted from less time in the oven. In earlier drafts, Qui-Gon didn’t exist yet, and Anakin was a teenager with an apparently more troubled personality. Lucas spent several years polishing the script into exactly what he wanted it to be. But some of his revisions may have actually made the movie worse.