I don't think any of the original characters need to be "fixed". They just need a writer that knows what to do with the years and years of development, both good and bad, and make something interesting from that.

Cyclops was the perfectly boring "Boy Scout" who grew up following and never questioning his mentor and surrogate father while eventually marrying his HS sweetheart. Then she left (died, true, but left makes this work better) and he had other relationships, and when she came back, he tried to pick up where they left off, only they weren't the same people as before. Along comes Emma, who taps into something in Scott that Jean never did, and they start an adult relationship far different than the fairy-tale idealized one he had with Jean.

On the Xavier front, Scott realized that Charles wasn't the perfect role model he'd always thought he was. Xavier lied, kept secrets, and used his abilities to manipulate others (all while claiming he wouldn't cross that line), and his vision, which appealed to teenage Scott, no longer agreed with the man Scott became.

To me, that character progression for Scott is pretty much perfect. He stopped being the wild-eyed idealist and grew into a realist because life happened to him, as it does for most of us.