I would really dig a "crossover" or callback of any kind of Mystic Quest...

[TeraRamis]

FFVII leads my list of crossovers, followed by Chrono Trigger. But even the latter is somewhat iffy, as overall, I'd really rather they not continue to muddy the water with NIER-like non-Final Fantasy nods. I personally think NIER is garbage - it's a predictable, emotionally stunted story layered on top of a bad bullet hell game. It had no place in FFXIV - certainly not before we get any acknowledgement of major pillars of the FF RPG lineage.