I hardly ever used Quistis or Rinoa...I've never been particualrly crazy about blue magic, so I sparingly used Quistis for the same reason I sparingly used Quina in IX and Kimarhi in X. Rinoa I...don't really know why I used her so little. I guess because I didn't care much for her limit break either. I like, NEVER used Irvine though, I think because the ammo thing bothered me.

I guess it's not so much I didn't use Rinoa, Quistis, and Irvine, but moreso that I used Selphie, Squall and Zell too much.