Episode 7 has found its writer last week in Michael Arndt who wrote fantastic stuff like Little Miss Sunshine and Toy Story 3, so there's that as good news.

All of the oldies from the original films have signaled their willingness to return if needed. But there's definitely gonna be a next generation, they do want the teenage boys and girls to buy their movie ticket too, after all.

Now this rumor surfaced (like many more will until it's all said and done): What if Vader returns? I agree with this article that making Vader the villain again would torpedo the thematic arc of the former films. But if he only shows up for guidance, as Jedi ghost for example, it's not really Vader but Anakin, right?
So I'd take this rumor with a grain of salt. Then again, Star Wars always has been Anakin's story. I'd say there is no way the next film won't be about Skywalkers.