https://news.avclub.com/gary-kurtz-outlines-original-darker-ewok-less-ending-1798221255
I get why Lucas didn’t want to kill off Han. It makes sense 30 years on, but killing one of the big three would have been a huge downer. Star Wars is essentially a fairy tale and good always triumphs over evil in those.
Well, this plan also included a very different sequel trilogy, with VII coming out not terribly long after ROTJ. It wouldn’t have been the ending.