When I read that Mark Hamill met with George Lucas because of Episode VII I remembered reading about an interview from 1983 in which George Lucas said that a possible sequel to Episode VI would revolve around an aged Luke Skywalker trying to pass on what he had learned, 40 years after the death of the Emperor. I still think that this could be the story for the new trilogy. 40 years after The Return of the Jedi, Luke Skywalker struggles with being the last of the Jedi. He wants to fulfill Yodas last wish to pass on what he has learned but he also knows that every padawan could fall to the Dark Side and Luke doesn't want to be responsible for the return of evil into the galaxy. Still he takes on a pupil and the one thing he feared most happens: His padawan succumbs to the Dark Side and "ressurrects" the Sith-Order. Luke has to deal with this and come to terms with the fact that there is no light without darkness. So maybe Anakin wasn't the Chosen One of the prophecy to bring balance to the Force. Maybe his purpose was to create a "blank slate". He eradicated both Sith and Jedi but one remained: Luke. This could not be the balance of the Force as at the end of Episode 6 we have just one of the good ones remaining - this is no balance. So what if it is Lukes destiny to bring balance to the Force? He is not the last of the Jedi but the first of a new order, having been trained without the constraints of the codex. By him creating a new Jedi Order as well as being responsible for the return of the Sith would bring the balance between good and evil.