Anger leads to the dark side. If Luke falls to the dark side, then the battle outside the Death Star is pointless. We see Luke abandon the mission on Endor because he knows Vader is going to find him. He gives himself up and is taken to the Emperor and there tries to avoid giving in to the dark side. He has a moment when his anger takes over and I believe he taps into the dark side, but then he lets it go and is not consumed. He refuses to kill. The scene on the Death Star is a chess match between Palpatine and Luke. The fate of the galaxy rests in the result. If Palpatine successfully turns Luke, all is lost. And somehow Luke hopes to turn Vader, but his primary focus is to keep them occupied while the ground teams destroys the shield and then Lando and Wedge destroy the Death Star. At the point when Palpatine should be focused on the battle, he is instead distracted by Luke and isn’t paying attention to his impending demise. Had Luke fallen to the dark side, the Rebels would have been wiped out.
So Luke’s part in the final battle is not as a bystander, but a distraction. He picks up his lightsaber and distracts with the duel until Vader makes it serious by involving Leia. Palpatine is completely focused on Luke and trying to turn him. So Luke really is a hero for his actions because he prevents Palpatine and Vader from staying involved in the battle raging outside. Palpatine doesn’t even noticed when the shield generator is destroyed. He’d rather kill Luke and ends up being killed by Vader.
If I was Luke I would explain it by saying that Palpatine had been controlling Anakin/Vader all those years and that he was the catalist that Anakin needed to free himself. That puts all the blame for Vader’s actions on Palpatine. And I think that the way Lucas wrote the PT that is what was actually going on. I think Palpatine used the force to tip Anakin to the dark side and then used the force voice on him to make him destroy the Jedi temple. Then after the duel, Palpatine used the force to keep him alive all those years. So when Vader killed Palpatine he killed himself… not just because of the damage from the force lightning.
We know that Anakin wasn’t quite so innocent and that he was teetering and about to fall, but Palpatine did not leave things to chance. Watch that scene in ROTS after Mace is dead and listen to sound effects added to Palpatine’s voice. He is not leaving it to chance but is using the dark side to manipulate Anakin and hasten his fall to the dark side. I think Anakin’s anger at Obi-wan is genuine and that he really did try to kill Padme. And in the end he thinks he did. So when the chance comes to save Luke - Padme’s son - he doesn’t hesitate or think of the cost. What caused him to fall is what ultimately causes his redemption. Luke was the cause of the fall and redemption both. With Leia, of course, but Luke was the child he knew about leading up to that final confrontation. Still, Luke could follow Obi-wan’s example and tell the story from a certain point of view. Not like there are any other witnesses to the events.
But without Luke being where he was, Palpatine’s attention would have been on the battle and he would have sensed what was going on on Endor and could have given orders to prevent the success of the Rebel’s mission. But because he was distracted by his Sith business, he ignored the battle and was destroyed. Luke didn’t destroy the shield or the Death Star, but he facilitated both by being where he was and doing what he was doing.
My issue is that the ‘Luke as distraction’ thing is something a fan would come up with to fill a plothole. It’s not something the movie ever expresses or even hints at (although it was in the novelisation). As I keep saying, I wish it had been a component of Luke’s farewell speech to Leia. All that Luke is concerned with at that point - apart from getting out of the way - is saving Vader. So I do like the theory, but I wish it was in the film.
I also have issues with the Dark Side and matters of aggression. I don’t think it would have been unethical for Luke to kill Vader and Palpatine outright from the get-go. These guys were slaughtering thousands of innocent beings. Self-defence right? At very least Luke should have had Palpatine in a headlock and forced him to order the shutdown of the DS cannon. If Han Solo had been in that throne room - or Chewie or Leia or Wedge or any Tom/Dick/Harry - they would’ve pulled a gun on those clowns immediately. They would have failed of course, but no-one would question their right to act in that way. The notion that a Jedi is automatically hamstrung by this suddenly unwavering notion of pacifism is ridiculous. When Luke destroyed the first DS - and all its inhabitants - you didn’t hear Obi Wan’s ghost-voice say “don’t shoot Luke - try to reason with them”. It was war.
I’m not with you on Anakin’s being controlled by Palpatine. My impression was that Anakin sold his soul and knew exactly what he was doing. In ROTS he clearly uses some pretty lame self-justification to make himself feel better when explaining things to Padme. In fact if I’d written ROTJ (and I’m sure everyone here is glad that I didn’t!) I would’ve had Luke come to the conclusion that there is no ‘dark side’ - just the choices we make.
But yes, the ‘Luke as distraction’ thing kind of works - I just wish it was firmly expressed in the film. It would have been awesome (IMO) if Luke had just spared Vader after the hand-chopping thing, and Palpatine had said something like “young fool, do you seek to bargain for your father’s life?”. Luke would smile and say “no, I am a Jedi - like my father before me. What I have bargained for is time.” Palpatine would suddenly realise that the DS is coming apart around him and then angrily roast Luke with lightning - prompting Vader’s reaction etc etc. Or something like that anyway…