Most of his attempts at armour design are impractical or impracticable, but then that's true of most costume designers who don't actually know how armour 'works' in practice.

I have the dubious benefit of knowing how to fight with swords etc, how to travel through the wild on foot, and how to make and wear the kinds of clothing actually worn by our ancestors who did both those things. As a result, I know all too well that many Final Fantasy outfits would be virtually impossible to fight in for long periods without bursting seams, or restricting movement. The FFVII outfits weren't too bad, but many of the game both before and after VII had costumes that no sensible combatant would willingly fight in.