On another note, a quote in the book from Richard Marquand suggests that part of Harrison Ford's motivation for wanting to kill off Han Solo was so that Leia and Luke could get together romantically. By that time Marquand knew that Lucas wanted Luke and Leia to be revealed as siblings, but he wasn't allowed to tell Ford that yet!
The idea of Han dying and Luke and Leia becoming an item is intriguing. It harks back to Lucas's older ideas for the future of the OT, during production on ANH, when he imagined Han leaving at the end of the second film and Luke and the Princess getting together:
I want to have Luke kiss the princess in the second book. The second book will be Gone With the Wind in Outer Space. She likes Luke, but Han is Clark Gable. Well, she may appear to get Luke, because in the end I want Han to leave. Han splits at the end of the second book and we learn who Darth Vader is...
In the third book, I want the story to be just about the soap opera of the Skywalker family, which ends with the destruction of the Empire.
By the time of ESB, of course, Lucas imagined that Han and the Princess would be the ones to hook up in the end. This was decided early enough that Lucas told Leigh Brackett that's what would happen. At the end of the Brackett draft Han still leaves--to convince his powerful stepfather Ovan Marekal to join the Alliance--but he plans to come back to Leia.
However, if you combine Han's death (and perhaps Luke winning Leia's hand) with Kasdan's idea of Luke taking over the Empire and becoming a benevolent monarch.... well, you can start to see where some of the Gary Kurtz rumors come from.
Of course, it shouldn't be forgotten that the very first rough draft for ANH--the one simply titled The Star Wars, now being adapted by Dark Horse--ended exactly this way, with the new Queen Leia and her consort Annikin Starkiller (the "Lord Protector") appearing gloriously enthroned in the royal palace of Aquilae.
(Mark Hamill was also interested in getting Luke hooked up. He gave Lucas a book full of drawings of alien creatures, with a handwritten inscription asking him to pick out a girlfriend for Luke from among the various aliens. It didn't work.)