I think the ultimate troof is that we're really thinking in the wrong spheres. We need to come up with new spheres that will seriously augment the magic line into something useful instead of a generic steamroller for the careful planner.
Therefore, I propose:
1. Douchetoolz Mana
A. Douchetoolz I: Freshness: Provides one health to city w/ caster present
B. Douchetoolz II: Cure disease: Why bother with a priest? It's the clap that gets the troops down when they're on the move.
C. Douchetoolz III: Stankonya: Transfers all diseased/plagued/withered promotions to units in surrounding tiles.
2. Bacon - "B" Is for Bacon.
A. Salting/Curing Raster: Plus 1 food for caster in city
B. The Gorge: Units in caster's tile gain the heavy promotion, percentage chance for disease.
C. Tastiness Inviolate: An archmage level taunt spell. Odors of cooking bacon waft to enemies in adjacent tile. Impossible to resist.
3. Permutationabilitationity Sphere
A. Alter terrain: Changes one tile to next level of terrain, like vitalize, only requires caster to be present in tile at all times.
B. Bestiality: Random chance to alter one or more units in stack into an animal w/ current promotions.
C. Zoo gone wrong: Chance to transform caster into great animal, e.g. dragon, manticore, great ape, or some other thing, bear, wolf, tiger, etc, with beastmaster-level strength.
Silly names, horrible ideas, but whatever. Laugh while you can.