However, I must say he dropped the ball back during ROTJ as well. It further fuels my theory that he just made up Leia being Luke's sister at the time because, if he had planned it, there would have been some mention of her being adopted at some point in the previous movies, or having actually mentioned her last name in the movie rather than just listed in the opening credits of the first movie. Instead, it just pops out of nowhere without ever having been mentioned before, and we're simply supposed to accept it!