Luke & Leia were never intended to be related. That's been discussed & proven a hundred times over through the years. Lucas had writer's block and ham-fisted a way out. He and other people in the productions have mentioned it in interviews plenty of times.

He also shot the "there is another" scene in Empire without even knowing himself who the other would be. It's typical of his think it up as I go style of film making. That's also been backed up with published interviews.

Someone coming on here and feigning seriousness when raising the question of the incest having possibly been around pre-Return and that it somehow proves all the Lucas' Original Vision bullshit is just a TFNer coming here to troll the board.

The reality of the film series is here;

http://secrethistoryofstarwars.com/book.html

Well-researched, backed-up with credible sources, and put together by someone who is extremely knowledgeable on all things Star Wars - particularly the history.