Geomancers are probably one of the most overlooked classes in the game because people fail to equip them properly. Yeah, give them some basic sword, normal clothing, maybe +attack glove? Worthless. Rune Blade, Aegis Shield, Magic Gauntlet, Flask Hat, etc, and have them leveled as a blackmage or summoner for most the game. Get to lv 99, turn them into a Geomancer, give them nothing but +MA gear, and watch their long range, free-costing, status-inducing attacks hit multiple targets for 150-200 dmg each. Think Orlandu or Agrias, with a little less POW, and a little more range and status effect variations.

At one point I made a team of nothing but Geomancers. By the end of the game, most battles were over before the enemy even got into attacking range.