Along those lines, remove the whole subplot about Darth Vader being Luke’s father and instead focus on the relationship between Vader and C-3P0. The big revelation is now:
“Obi-Wan never told you what happened to C-3P0’s father.”
“He told me enough. He told me you killed him!”
“No, I am his father!”
Even better, just replace Luke with 3P0 for any scenes involving Vader.