Quote Ohio chick: considering Fen and Summer grew up together I would like to see them as a couple. After he has rehab Summer can be to him as Phyllis was to Jack a supporter. I think Kyle is to old for summer. Also, I don't see the sparks between Kyle and Summer. They could get a new Fen or mature this one a little.
I'd be in favor of a recast of Fen. Heck, they have recast more than half a dozen other actors for ones who weren't half as good as the ones they replaced, so why not have a recast for an actor that could be improved instead. I never cared for the current actor playing Fen and I'd like to see Summer with him rather than Kyle. I think you're right about Kyle not being right for Summer.