According to the Guardian today, at a recent convention Gary Kurtz, the writer of Return of the Jedi, revealed the original plot to the movie, which was that Han Solo would die halfway through in a raid, Princess Leia would have difficulty adapting to her new role as leader, and Luke Skywalker would walk off into the distance an embittered loner. That last part certainly fits with his presentation in the movie. I don’t know about Han Solo though – people like him are meant to survive anything, it’s part of their mystique. Someone who can say “I know” just before being frozen, possibly forever, is the kind of guy who doesn’t die in mid-level base raids.
So, would the movie have been better done this way? Note the alternative storyline doesn’t preclude ewoks.
I think Skywalker’s end, particularly, would suit him better, but I also think that Vader’s redemption was a really important part of the 3rd movie and there’s nothing in the alternative described in the Guardian to suggest what happened to him. I actually liked the existing end of the movie, with the rebel alliance successful, Vader redeemed, and Skywalker a bit of a grump. The only thing that spoils the movie in my view is the ewoks, and they don’t spoil it much.
But in the decision about how to end the film, there is a hint of the real tragedy to come: Lucas decided to give it a happy ending because toy sales were very high. It’s really hard to work out what happened to the mind of a man who allegedly wrote the first 3 movies as a film representation of the journey of the hero, as described by that academic (Campbell?) and how he slid so far in the making of the new movies. Proof of the existence of the Elder Gods, I suppose.