Yes and Blackmage totally can't make it into the game without elemental wheel ! Oh wait...

A simple way to have Geomancer while keeping the original concept would be ( like BLU ) to have them learn skills from the earth during their quest that they can use later, they just have to find a caster gameplay et voilà ! Obviously they'll get away from the original job concept, or else warrior would only spam attack buttons, mages would spam Ultima or meteor, summoner would keep summon Bahamut or Odin, etc...