Besides, if Hayden returns as Anakin's Force ghost then technically we'll still see Darth Vader in the new movies sans the black suit. And the Dark Side.
I get the feeling that since George said the SW Saga was really the story of Anakin more than anybody else that we'll continue to see him in spirit form giving advice and wisdom to his son and daughter as they try to live and forge ahead in the post-Empire galaxy.
That implies the ST will be about Luke and Leia and not a future generation. I think the latter is more likely.