Which characters do you typically ignore through the game?
For me, in Final Fantasy VI, it's quite easy to just ignore Gau and never use him if I don't need to. I don't care much for his rage techniques. And his Mowgli syndrome irritates me.
VII - Although I've really only played this game twice, I still don't think this game gives you much reason to use all of your characters. Through my last playthrough I used Cloud, Yuffie and Vincent all the way until the end. Other than that, I almost never find Barret, Tifa, Red XIII or Cat Sith. I find them all to be annoying. I like Vincent because he's quiet. But I don't like this game much so I haven't really experimented with the characters anyway.
VIII - When I first played this game, I used only Squall, Zell and Rinoa, but over the years I've grow to love all the characters and I've learned how to be able to use them all pretty evenly.
IX - I try to use all the characters pretty evenly, but Amarant just comes into the game far too late. I could grind to make him more useful, but I don't like enough to even care.
X - Using everyone in the game wasn't very hard, especially because you can switch members in battle and your experience isn't divided by how many characters participated. I like this game. :D
XII - Pretty much the same as X. I don't care for Penelo but she isn't hard to use in battle.