I can see the layers of ambiguity, morality, and symbolism working in ROTJ. While I really do like that film (and truth be told, it was my favorite of the 3 growing up), it is a bit weak because it doesn't go for the gusto and pulls some punches. You have Luke in final confrontation with the forces of Evil, his father, and his father's father figure, along with Luke's own misgivings and ambiguity about staying on the Light side or going to the Dark side. Should he kill his father to become his father? Should he or can he redeem his father? What is his destiny? The morality of the film should have been straight out of ESB, and have gone dark then to light or at least grey. Taking into account the early drafts, Luke should have fallen to the dark side, and then been redeemed at the end.
Perhaps Luke, remembering his earlier insistence Vader could be redeemed, keeps more self-control when he beats his father down.
He doesn't see the robotic hand and realize he's in danger of becoming his father. However, given his focus on his dad, when Palpatine does his whole "take your father's place" thing, Luke says "no" dramatically and engages Palpatine in battle. Given how he already used one Dark Side power already in the film (the Force Choke, in Jabba's Palace), maybe he can summon Force Lightning?
(It wouldn't be that much, just enough to surprise Palpatine and show how close to the edge Luke is getting.)
He momentarily triumphs (due to Palpatine's age and overconfidence), Vader starts going on about how he's joined the Dark Side and they CAN rule together, and *that* is Luke's system-shock. He refuses to finish Palpatine, saying the Jedi don't kill helpless enemies, and then Palpatine does his "so be it, Jedi" routine and overpowers Luke.
Palpatine, even more PO'd because he'd been bested, however temporarily, is even more deliberately sadistic than in the canon film. This awakens Anakin Skywalker and we get the reactor-shaft end that Palpatine got in the canon film.
Is that properly morally ambiguous?
