Everybody except the most nostalgia-blinded people know that the prequels are atrocious. Said nostalgia-blinded people often cite that the prequels did everything they needed to do : explain the backstory of the original Star Wars trilogy. I believe this is the exact reason why the prequels fail.

The original trilogy thrived on mysteries. The people act like normal people. Knowledge of the setting flows organically from character to character, and when something greater is implied, it really makes your imagination wonder and just makes the galaxy seem vast (ex: C3P0 introduces himself as Human-Cyborg Relations, which implies relations between cyborgs and humans in the Star Wars universe is strained).

Darth Vader is the ultimate example of the less-is-more storytelling technique. You don’t show the character became the way that they are but you show they are affected by their own motivations. Darth Vader is a half-man half-robot master of evil who refers to himself (Anakin Skywalker) in the third person, fights his own son, and couldn’t even believe he could be redeemed until the last moments of Return of the Jedi.

The motivations needed to justify Darth Vader would have to be so incredibly strong that it is almost impossible, especially when the fans themselves create their own little stories that are better to them than anything anybody could come up with.

Even if Anakin’s fall was told really really well, it’s still just backstory and more of what we already know! Lucas dedicated three movies to ruining the mysteries of the original trilogy and failed even more miserably than anybody could expect!

So what do you do? Simple. Make a story that doesn’t just explain another story. Look at Knights of the Old Republic! It’s set in the past but isn’t defined by it. Forget the Clone Wars! What about the Sith Empire? Avoid spoiling any OT mysteries and just make a damn good story set before the OT!