I dunno if square will ever touch xenogears since xenosaga existence might make things weird? A port to modern hardware would be nice (maybe with a speed mode since there's pretty long stretch that I wouldn't speeding trough). It would ultimately be nice to have a bigger project with restoring all the lost content, but I doubt that'll ever happen. I do think a full blown remake would lose a lot of the charm the game had, I can't help but think they would simplify a lot of the game story and weirder element.
I always find it weird that square doesn't port more of their stuff to modern hardware, how hard is it to just make straight port of PS1 game? Couldn't they have a small division that would just go trough their catalogue and update stuff on a semi regular basis? Maybe with capcom just remaking every RE game and doing apparently pretty well from it square might get a bit more serious at that. They have been doing some stuff, but their choice are so incredibly weird, they focus a lot on the saga franchise for some reason (there were just leak that saga frontier 2 is getting ported) and the mana franchise (trial/legend in recent year). They also do so very slowly, maybe by 2040 I'll get a port of thread of fates.
Dunno why FF6 never got much attention from SE, maybe 7 right after sucked out all the attention? Maybe it didn't do really well on release and only gotten more attention over the year. A lot of what make 6 interesting were unusual choices the game made (split party, multiple main character, bad guy winning, non linear second part) which maybe square think it wouldn't feel as fresh on second take. Square does seem a bit more minded to revisit older FF, with the pixel remaster and FF9 getting an anime with some rumor of a sequel (blerk).