Forgot about Geomancer, yeah it would be awesome to add. Though it's ability list would be very short.

Weapon- Bells
Spells listed from Tatics
Pitfall
Waterball
Hell's Ivy
Carve Model
Local Quake
Kamaitachi
Demon's Fire
Quicksand
Snowstorm
Gusty Wind
Lava Pit

Fifteen Ability "Gaia's protection" Party/Alliance becomes impervious to all attacks for a short duration.

Gaia's Wrath- Next Geomancy spell damage is greatly increased. 5 minute recast

Terrain Walker- 1 minute aoe buff that allows the party to ignore floor damage for 2 minutes. Pefect form AV, and it forces people to have to pay attention or they might die.

Gaia's Cloak- Invisible/Sneak similar to Spectral Dance for Dancer's in FFXI.

Geomancy would have to work like black magic spells. If they were random like FF5 or Tatics or area based then you might end up healing the boss which no one would want.