I would also keep the sister stuff to a minimum.

I can see editing off the Yoda line, "there... is.. a..nother.. (sky.. wal..ker)". To HINT at someone else, who could be ANYBODY, would keep the audience on their toes.

Again, cut out Ben's scene and leave it to Luke to make the revelation; he has pretty much the best lines anyways, "My family has always been strong in the Force. My father has it; I have it... and my SISTER has it.." whereupon Leia makes the connection herself.

When Luke is confronting Vader and Vader is searching for him underneath the Emperor's throne, delete the "SISter" and "your feelings have betrayed you" lines and just have Vader end his speech with "if you won't turn then perhaps SHE will." This will save the Leia card for the very last moment, punching up the dramatic element of the scene (as in Vader is teasing Luke by hinting at what could he have read in Luke's mind until the very last moment)

I can see not adding Sith eyes to Luke, but we still need to see just HOW angry he is and show both small and large pieces of machinery ripped from the walls and being hurled into Vader as Luke simultaneously pounds away at him with his lightsaber. To have Luke do to Vader what Vader did to him at Bespin but exponentially would show just how powerful Luke really was as well as explain how EMPIRE Vader could be defeated so quickly.

Iam thinking along the lines of DRAGONBALL Z with the Gohan character - no so much copying the visual theatrics but how the character of Gohan was relatively weak until he was pissed off or a family member was beaten to near death, whereupon he would "hulk out" so to speak.