You know the most flabbergasting thing about saying “Luke killed his father/was totally ready to do it to Prove a Point” (aside from the fact that you’re factually wrong if you claim that), and have it be something negative, is not just that he literally doesn’t do it, it’s because that if Luke had done it, it’d have been the traditional ending to his Hero’s Journey.
Luke killing Vader and Palpatine is what a traditional hero in this sort of setting would do.
And the whole point is that Luke DOESN’T.
He doesn’t kill one (or both) of the penultimate villains of the story. He doesn’t do the Right and Just and Proper thing and kill the villain, who is is father. It would’ve been treated as Tragic but as Necessary.
He doesn’t, and instead asks for a rescue, rather aborting the end of his traditional hero’s journey and turning it into something else. And you want to use that as something negative?
See this is why I find Luke and his arc much more complex than what many people give him credit for. Luke subverted many tropes, and one of them was killing the bad guy. By choosing love over revenge, and accepting his own Dark Side instead of repressing it, Luke managed to do something different and equally effective than merely killing the two villains. Some people say “What a dumbass, he threw his lightsaber away!” and it’s like: “NO, YOU’RE MISSING THE POINT!”, Luke’s greatest victory wasn’t killing the bad guy, instead it was acknowledging the darkness inside himself and accepting it as a part of him without letting it consume him completely, as well choosing love over revenge, which, given the context that the movie and the new EU has given us, it wasn’t an easy choice: prior the whole Father reveal, Luke genuinely wanted to kill Vader for revenge for what happened to his father (for what he believed), his uncle and aunt, his childhood bff Biggs, Obi-Wan, for the damage done to Leia and later Han….and even in “redemption plan” he still was a bit to succumb when Vader tried to put Leia in danger. Killing Vader would had been the easiest choice, but he chose no, and of that, he made something even better.
And that’s why Luke is awesome.