Mostly I just figure the Endor stuff would have been a lot cleaner and less cute, I guess maybe Han would die but who cares, and Luke would struggle with the dark side more while Leia has to save him from himself. With a Vader redemption I imagine a Luke moral tug of war could be fun but a little too packed for a wishy washy side conflict for Luke just like the actual ROTJ, it just isn’t believable Luke would go to the dark side, Vader’s redemption is more impactful anyway. I agree maybe more time spent with Luke training, specifically building his new lightsaber onscreen, but I would need to know more of Kurtz’s thoughts, now I’m just going into my own wishful thinking.