I will never not be so impressed with Mark Hamill’s acting, especially in the third act. He is so convincing in portraying Luke’s zen determination, but always reminds us with subtle micro expressions that Luke is still afraid, deep down.
I think that’s important. Luke not emotionless, but he’s (almost) mastered the art of regulating his emotions. He uses his compassion for his father to attempt to reach him, but doesn’t lose control until Vader threatens his sister. When he falters, lashes out in rage, he then stops, reflects, and let’s go. Being a Jedi is about being in balance with your emotions, and Luke captures that so perfectly.
It’s hard to think of anyone else who would put themselves on the line to save an abusive father who tortured and killed people he cared about, all because he knows of the conflict that his father represses. That’s a hero.
RotJ is the movie that really elevated Luke from a good character to a great one. It’s why I don’t abide people claiming that Luke is generic or uninteresting. Luke is great because he doesn’t fit the stereotypical image of the knight or warrior. He’s reserved and soft spoken, and conquers the villain through compassion, not force. He is what a knight would be in an ideal world.