I’ve said this before but a simple dialogue tweak would fix this. If Luke had said to Leia “I have to turn myself in, I’m endangering the mission. The Sith can feel my presence and know that we’re here. I’ll allow myself to be captured - Vader will take me to the Emperor himself and I will make sure he’s on the Death Star when the attack is launched”.
That would just make Luke a “captain obvious” to those in the audience who cannot make 1+1=2 on their own. On the other hand, it would ruin things in-universe. Luke probably knew and accepted that it was a suicide mission and that he would most likely die if the Death Star was blown off (whether or not Vader was redeemed). Why the hell would he tell such a thing to Leia and make her upset before such a crucial mission she was about to undertake? The way he handled it was very wise; he did not lie but he did not tell her that he is going off on a suicide mission either.
I’m not sure telling her that the guy who tortured her and stood by while her homeworld was obliterated was a) her father and b) strangely worthy of a crack at ‘the good side’, was much better than Luke taking on a heavy mission.
I must be the audience who can’t add 1+1. Luke’s only stated mission is the redemption of Vader. While insane violence is occurring outside, Luke’s primary focus is not losing his cool and avoiding a confrontation with Vader. When he finally kicks Vader’s butt - rather than follow through by doing anything proactive in terms of the war - Luke throws his weapon aside and declares himself a Jedi. People are being incinerated by a super-laser by order of the man standing before him and Luke chooses to disarm himself and declare his own enlightenment. How is any of this remotely helpful to the thousands of sentient beings suffering at the hands of the Imperial juggernaut? What in all this makes anyone think that Jedi Knights are a good idea, especially in a war situation?
Indeed you are the audience member that can’t add 1+1. I’m pretty sure Leia knew that Tarkin and The Emperor had more to do with what happened to her and her homeworld than Vader did (acting within their orders, not questioning them due to extensive brainwashing/basically being their slave). Remember how Vader criticized the Death Star at the meeting? If he was calling the shots, Tarkin and The Emperor wouldn’t have their plaything.
Also, for the “Luke could save so many lives thing,” what’s to say that killing The Emperor will stop the battle? The Star Destroyers, Death Star personnel, and Endor ground troops will still act under their initial orders to fight. Whatever Luke does, many will die in the fight. What he will do really doesn’t impact the battle outside and that’s fine.
Again, I maintain that you’re engaging in bad-faith criticism that really misses the point of the movie and the series, so I respectfully disagree with you.