Thinking you mean Episode 6?
But I dunno man, I think Luke's character is pretty well established from the beginning of ROTJ to the end... He's a Jedi, flat out. So there's no twists or turns for his character, he's effectively the contemporary version of Obi-Wan Kenobi (at least, in his own way).
I think the movie is really meant to show Darth Vader's character develop from being this ruthless Sith Lord in A New Hope to being a conflicted father in ROTJ. I also think we see Han's character turn into more of the "General Solo" to partner with the woman he's now obviously in a relationship with, in Princess Leia.
Overall, I think ROTJ gets a lot of heat because of the Ewoks and the level of commercialization but is still a fantastic film.