I really hate the idea that only young people can star in movies.
I don't think that's the case at all. But I do understand studios 'playing the percentages' by casting younger actors as the central characters when building a movie series that could conceivably run ten to fifteen years.
We're all fragile, but the younger you are the less likely you are to 'expire' or run into an affliction that could complicate the process.
This is not about rehashing the old movies, this is about living in the past or writing a new story. Each trilogy of the series should be about a separate generation of the Skywalker family.
What I don't want to see is some fanboy crap movie that tries to rekindle the past by regurgitating things that have already been done. Rather I want to see a continuation of the story with new characters and themes that tie nicely with those that have come before without treading over trampled ground.
(How's that for mixed metaphors?)