Xenogears and Skies of Arcadia.
But, as we saw with Chrono Trigger, sometimes sequels aren't a good idea - even when made by the most creative guy on the team - IMO, creatives like Kato need and organized force like Takashi Tokita to be successful. Not that Chrono Cross is a bad game, but I find it utterly fails as a sequel to Chrono Trigger - and IMO, the DS Chrono Trigger felt a little sullied by putting the tie-in new ending.
A proper sequel to Skies of Arcadia is impossible after the unfortunate passing of Kodama a few years ago.
Xenogears has a number of spiritual successors - three, if you count Xenosaga, Xenoblade Chronicles X, and the Xenoblade trilogy. I think proper successors to Xenogears, and by the authentic development team, would be ideal. Most of the Xenogears core team is still with or aligned with Monolithsoft. They could conceivably get all of them back together, even Kunihiko Tanaka might consider coming out of retirement (he retired young).
I describe myself as a little dose of toxic masculinity.
