I personally don't want a Chrono sequel unless
- Yuji Horii, Hironobu Sakaguchi, and Akira Toriyama all come back,
- They have a solid idea they're confident about on what this new game should be, and
- Characters are kept to a small amount like in the first game so they all get adequate character development, to avoid another Chrono Cross situation where barely any of the 40-ish characters are developed.
Masato Kato doesn't have to come back but Yasunori Mitsuda's return would be appreciated, but in either case I think new people can step in.
Chrono Trigger was a one of a kind game that I sincerely think can't happen again, the circumstances were too perfect and it almost feels like destiny that everything came together so well. So I don't really want another Chrono game and have moved onto other stuff.
As for Chrono as a playable character, I'd be okay with them as a Mii costume, weirdly enough. The Mii Swordfighter already has a few recovery specials that resemble some techs of his, both the spinning slash (Hero's Spin) and the jump dive (Stone Scabbard). The wind slash he does could be represented with Gale Strike. Stuff like that. Crono would only be missing his lightning magic which is admittedly a bit of a shame, but it's workable enough for me if it were to happen.