Alter the dialogue when Luke confronts Vader in ROTJ, in order to increase continuity with ROTS:

LUKE:
Come with me, father. I know there is good in you, let go of your hate!

Vader pauses. He’s heard those words before, but from where? Then, he remembers.

VADER:
Joe once thought as you do.

LUKE:
Wait… who’s Joe?

VADER:
Joe MAMA! OOOOOOOOOHHHHHHHHHHHHHH!!!

Vader continues “oooooohhhhh”-ing for the rest of the scene, as Luke walks into the elevator shaft, a look of disappointment on his face.