In my mind Luke is another way in which the ST has made up for the problems of the ST. Much like Han (who has next to no depth in ROTJ), the Luke of ROTJ is simply not as interesting as the one in SW and ESB. He basically goes from fucking up big time at the end of one movies to being uber confident and wise at the start of the next. At no point does him turning to the dark side in ROTJ seem like a plausible possibility.
Huh.
Vader toying with Luke about Leia was really eating at his mind, which really sent Luke over the edge there. The only thing that stopped Luke was seeing both Vader’s chopped off hand and his cybernetic hand, realizing that Vader is still a human as just as much as Luke is, even underneath all that machinery; challenging Obi-Wan’s line of, “He’s more machine than man.”I know that moment (I know that film by heart). It’s great. But nothing that precedes it would lead you to believe that Luke might actually finish Vader off and turn.
But saying it’s not “plausible” seems like a disservice to how we saw Luke in ROTJ. Unless I’m misunderstanding you, it sounded as if you’re implying Luke struggled very little by the temptations of the dark side and effortlessly accepted the light all the way through, when in fact, the mere thought of Vader doing anything to Leia greatly sent him over the edge. All that rage was pure seduction of the dark side. If he had not struck Vader in the spot that he did, it’s fairly likely he would had turned.
Vader’s hand chopped off by Luke = Luke forming a connection of empathy, thus not going full dark side
Vader’s hand not chopped off = Luke most likely believing that getting rid of Vader will save Leia and his friends