None of the equipment is missable anymore thanks to the Treasure Wheel. I think you can get the Zodiac summon and Ultima spell from Rendezvous battles, though I'm not 100% sure. And if you lose a party member, you can always regain them on a New Game Plus playthrough.
So there are fewer missables overall. None, if considering NG+.
So there are fewer missables overall. None, if considering NG+.