I look at Geomancer I think of all those buffs...
Plus with Cura becoming Nuture, I'd see no reason to hop onto WHM anymore. Sacred Prism + Cura = Healing + that regen effect which makes whm unique.
And those buffs, basically make a tank invincible for a couple of seconds with the right abilities.
However, with Geomancer, we'd probably have to introduce some kind of Damage reduction cap, cause almost every one of those abilities offer some damage reduction ranging from 25-75%.

If maybe the buffs were nerfed a little, it's make a super addition to a party set up that uses 2 CNJs already for healing. Allowing one to main heal, and one to sideheal and support.