Extra states do offer some building diversity so I wouldn't suggests putting those extra points all in to %elemental damage. That's boring.
But here's my though(not sure does the current system support these tho)
Fire as another "Violence" type of element, get magic armor penetration(which totally not a thing now)
Water as a damage/heal two-sider get cost decrease to support more spell spam.
To be honest, on my second thought ,that's it.
Earth, well, Earth mage Tank isn't a new thing, just bit of sad they got no MDEF. And one none cannon element is totally acceptable
And Wind's Eva and Crit still useful on mage if you don't want to get one-shoted
Light, Dark, Mind got their role
Thank for listening my yapping