I could see the Geomancer further developing abilities toward an offensive nature. They might have an innately high INT and a severe drop in MND to reduce their effectiveness as healers.

But abilities like Tornado, that may be like an AoE DoT.
Some type of ability that debuffs resistance to earth, water, and wind, possibly an attack spell with the effect built in.
Or like the thaumaturge/BLM Apocastasis to buff earth, water, and wind.