You’re pretty much intentionally handicapping yourself in FFIX if your team isn’t Zidane, Garnet/Dagger, Vivi, and Quina.
Vivi's worthless. Black Magic as a whole in the last two chapters of FF9 is worthless. Eiko eventually gets the Maiden Prayer accessory which trivializes the rest of the game. So few enemies in the last half of the game have wind resistance that she no longer has opposition when it comes to pure damage. For 30 MP she can one shot just about everything by level 70. If you run Dagger and Eiko together they breeze through Memoria because every boss is either ice, fire, wind, or holy weak. Kuja's the only one who isn't, but he doesn't resist any element so it's a field day on how easy he is. The game pretty much gives you max Opals and Topaz, and it only takes a little bit of synthesizing to max Sapphires, so Fenrir, Ifrit and Shiva blow through the game with ease for you.
The turtle in Shining Force 2 is one of those what if characters. His Monster class is fun but you really have to grind him to be worthwhile. Best way is to wait until the chess board battle and the defense ring to aura and gain him up to level 30 before promoting.
Ox and Gobi in Breath of Fire 1 serve only 1 purpose, to be morphed with Karn. Ox is too slow to be great, and Gobi is just too weak over all and his magic can only be used under water.
Jean in BoF2 is worthless, Spar is pretty close to it as well. The first two BoFs did a good job of making your non-team characters useful with the merging abilities.
Nina was annoying as shit in the first half of BoF3, but got better personality wise in part 2.. and then was completely useless because your hero gets healing magic and makes her worthless.
Nina sucks again in BoF4 but this time you can swap her in briefly to do a mass heal and pop her back in to the back row where she belongs.
When it comes to FF4, the GBA version really highlights how mediocre your final team is. I swapped in the twins in place of Rydia and Rosa, and bounced Edge for Yang. The caster twins are twice as fast at casting spells, and Yang smashes Edge's damage as well as having absurd HP growth Edge sorely needed. Just laughed my way through the final dungeon. I can't tell if this was just oversight from the design team with how quickly the twins magic stats grew, or if they purposely nerf the final team to make the moon difficult.
