I think the thought of no second Death Star is ludicrous. Anyhoo - Kurtz has his own imagination, but this was George's baby from the start. It only took a nose-dive in 1995 when he started censoring his opus - just before he went and started messing it up.
Luke and Leia not being siblings? The Falcon going in a blaze of glory? If it had been made that way, ESB and ROTJ would have made ANH look like Pee-Wee's Playhouse.