Hayden in ROTJ cancels out the moral of the whole movie. George Lucas back then was not as secular and was a lot more focused on the moral lesson.

Darth Vader DID become good at the end when he sacrificed himself to save Luke. That's what "Old Anakin" as the ghost shows.

Luke: I've got to save you!

Anakin: You already have, Luke. You were right...you were right about me.

Growing up I always assumed that Anakin meant that Luke saved him from going to hell or something like that.

But whatever the original intent was, Hayden at the end completely cancels it out.