The big script thing Lucas has peddled isn’t true. The original Star Wars sequel was called Star Wars II by Leigh Brackett, and Darth Vader wasn’t Luke’s father.
In fact if you read the story conference for Splinter of the Mind’s eye, everything we’ve been told about the Saga of Darth Vader goes out the window.
The script from 1974 Vader was just some general, and Valorum was the Sith Knight. Luke was an old General.
I’m glad at least the secret history of Star Wars is out there for people to read who were only given a certain point of view.