Anchorhead said:
He [Lucas] wrote, filmed, and released the "no, there is another" scene without giving any thought to where it would go or who 'the other' actually was.
Actually, Kershner shot it. And (I think) Kasdan wrote it and (I'm certain) had the idea that Luke would go off on his own to find this "Other" at the end of Jedi. Good stuff.
It's Lucas's heavy hand in ROTJ that began to show that Star Wars is better when he's less involved.