There is one spell in the healer's lineup that doesn't fit with the progression of the life mage. The healing spells are (cast by a life mage):
Dryad: X mana - 200 health per X Sprite: 1 mana - 30 + 270 health in 3 rounds = 300 health per mana Fairy: 2 mana - 420 health = 210 health per mana Satyr: 4 mana - 860 health = 215 health per mana Regeneration: 5 mana - 52 + 1101 health in 3 rounds = 230.6 health per mana
Regeneration simply doesn't fit into the lineup because the efficiency is barely better than the instant heal spells and nowhere near the efficiency of sprite. The "over time" component of a damage/heal over time spell must be counted as a cost, or they aren't worth casting.
My suggestion would be to make regeneration cost 4 mana and heal 1300 or so health for a 325 health per mana efficiency; a nice upgrade from sprite. As it stands, Regeneration costs too much for not enough healing to go into my deck.
P.S. I didn't include Unicorn since its efficiency is based on the number of people getting healed, and also I think it's pretty well balanced.