A new and intriguing interview with Craig Miller, the Director of Fan Relations for Lucasfilm back in the day, and also the man who wrote all of the Fantha Tracks newsletters.
He also talks about Lucas telling his plan, at the time, for Return Of The Jedi…
“The biggest thing was, as you mentioned, that Boba was intended to be the main villain in Return of the Jedi. That film was going to be about rescuing Han, dealing with Boba, etc. The redemption of Darth Vader and overthrow of the Emperor was intended for the next trilogy. But when George decided in 1980 not to do that next trilogy, Boba Fett became expendable and those things had to be dealt with in the third movie.”
and some other intriguing stuff in the interview too…
https://starwarsinterviews.com/star-wars-crew/craig-miller-lucasfilm-director-of-fan-relations
(Both the ‘Original Trilogy’ and the ‘Star Wars Crew’ sections of StarWarsInterviews.com are well worth checking out too.)