ATMachine said:
Lucas eventually decided to get rid of the Imperial city-planet altogether, which Kasdan didn't like:
Lucas: Just having the moon and the Death Star and not having Had Abbadon at all is... then you can have Vader's fleet, a limited number of starships out there. It's out in the middle of nowhere. It justifies the primitive moon. Right now, Had Abbadon is getting in the way of everything. It's cumbersome. And I like the idea that the trap is that the rebels think they're fighting a half-finished Death Star.
Marquand: It's wonderful.
Kasdan: I think Had Abbadon is worth saving. I think it's worth destroying the nerve center of the Empire. Forget the Death Star.
Lucas: But then you're still dealing with the question as to why have the fleet? The thing about the Death Star is it's so manageable. The planet is not manageable at all. It is too big to be manageable.
Kasdan: But it's much more interesting and it is new. The look of it is new and the idea that it's bigger than a Death Star is interesting.
Lucas apparently thought that he had to choose between one of two set-pieces going into the film: either the immense Imperial capital world-city of Had Abbadon, or the lush primitive jungle moon of the Ewoks.
We know which option Lucas ultimately chose, but Kasdan repeatedly argued for going the other way--keeping Had Abbadon and dropping the Forest Moon (and the second Death Star) entirely:
Kasdan: I think that we have to break out of here somehow and think of a simpler idea. Maybe get rid of the Ewoks.
Lucas: I know they're one of the things that are causing trouble.
Howard Kazanjian: Let me ask you a question: Just for five minutes, pretend that the Ewoks don't exist. What would we accomplish?
Lucas: Then you have a giant hole in the script that we have to fill with new ideas.
I completely agree with Lucas on "Imperial city vs. remote moon" argument. Final battle on imperial city wouldn't be "something new" but rather something very casual on predictable. On top of that unrealistic.
But obviously I agree with Kasdan on Ewoks. It is very interesting to see that Lucas did not inherently oppose the idea of getting rid of Ewoks. According to this conversation, he even thinks they are causing the trouble.