If I am to speculate a bit further as to how we might see the 6 movies as an integrated whole chronicling the life of Anakin Skywalker, episode 3 will be the great tragedy where the hope of his generation, the Jedi everyone puts their faith in, becomes irretrievably corrupted as Darth Vader by the Sith Lord.
To make a fool of myself, I believe that we now will see what will actually happen to a Jedi if he loses control over his hatred in front of a Sith master..
That will be Palpatine's great coup; it is the opening into Anakin's mind he needs in order to set the moral warping process going in him, which irreversibly it will seem transforms him into Darth Vader.
That is, a new layer of meaning will be given to all those moments in movies 5&6 where alternately D.V. and the Emperor tries to provoke Luke into strike out with his hatred.
Prior to Vader's rebellion, the Emperor suffers a minor setback: the new Jedi refuses to walk into the trap his father walked into years ago.
It's only a minor thwarting of his will, though: The emperor is perfectly capable of handling the crisis, but would have liked yet another, soon-to be devoted, acolyte.
But something starts happening with Luke's refusal the Emperor couldn't conceive possible:
Darth Vader receives a shock, he is transfixed, suddenly he starts remembering through Luke's example what it meant to be a Jedi..
While the Emperor is angrily sizzling Luke to cinders, D.V's mind is spiralling along paths he never knew still was there, and he is brought out of his reverie by his son's anguished cries of pain.
Finally, "the old hope", Anakin returns and fulfills his own destiny.
In essence then, I regard Luke as the Lightbringer, who comes to the one who had fallen in the Shadow, and guides him back.
Luke's world will be empty of friends and mentors, but hopefully he will manage to effect the return of Jedis in their old roles.
That, at any rate, is how I regard the story.
I'm probably wrong..
