That story conference transcript is just...wow. I'm surprised Star Wars Insider even published it.

Per Lucas, Vader is pretty weak and expendable at the end of a possible sequel with zero ties to Luke. And Leia is just as expendable and almost a throw away character! And of course there should be a romance between Leia and Luke. As for Han, who cares we'll throw him into another story. The viewpoint of the gallant hero on alien worlds shows that Lucas was thinking more of European comic books like Valerian and Moebius as his influence and not so much space (which is boring per Lucas).

Here's where Lucas went from all this:

1. With Vader as the main bad guy in Empire, he has to choke people all the time to show how awful a person he is, since he just stood around in the first movie and didn't do much, per Lucas. They have to build him up to be a great villian. The real slimy bad guy is the emperor who we get a glimpse of in ESB and then in Jedi. Maybe Lucas always thought Vader was a poor villian during the 77-83 period??!

2. The Wizard of Oz motif was carried over to Jedi when they unmask Vader and Sebastian Shaw looks almost exactly like the Wizard from the 1939 Wizard of Oz (in my humble opinion, it was also my first reaction to his appearance as a kid).

3. Everything else about Empire (and then Jedi) was made up on the fly. Since Leia was always expendable making her Luke's sister was no big deal.

As the years went on, I think Lucas ended up really liking Vader and probably thought he stole the show (which he pretty much did). So his next three films ended up being entirely about Vader.