Doesn't sound realistic. And I don't think it'll solve anything substantial anyway. Maybe Mark Hamill is too old to reprise his role again, or maybe he isn't. But Keri Fisher is gone, and I doubt Harrison Ford will consider doing it again.
And for an alternate timeline to occur, you'd usually involve time travel. I don't think I want to see that element added to Star Wars. Might as well prevent Anakin from turning to the dark side, instead of just stopping Palpatine from surviving then.
I would kinda love saving Anakin from turnig to the dark side and letting him raise Luke and Leia in peace. I bet most fans wouldn't like such a thing, though.