It feels like a lot of the spells in this game are underpowered. By "underpowered" I mean that they (1) do very little for their mana cost, and (2) don't scale well with increased unit power in the mid and late game.
There are lots of curse, buff, and damage spells with minuscule effects like -3 attack or 6 damage. Unit stacks just have so much hp and damage by mid game that they completely overshadow these spells. Examples include:
Thunderstrike: teleport to target location and do 5 damage to surrounding enemy units.(+2 per air shard).
Storm: strike a random enemy group for 20 damage (+4 per air shard). 1 turn casting time.
Burning hands: does 8 damage to up to three adjacent enemies. (+2 per fire shard). I could consider using this in one of the first battles, but it rapidly loses effectiveness.
Flame wave: 5th level spell, does 4 damage (+2 per fire shard) to all enemy units. This for a 5th level spell!
For some of these, damage is ok for early game, but doesn't scale well. Every damage spell without a +lvl bonus feels pretty weak. (Sunder is the best damage spell in the game, but only works against some enemies). With the (too big) warlock bonus of 50% extra damage, other damage spells can also retain their usefulness later. Also, on a huge map with lots of mana nodes, the damage spells can again become useful in the late end game when you have like +10 fire power. (Then even Flame wave will be really good).
On the other hand, the spells which affect percentages like shrink or growth remain usefull for the entire game. Slow and haste are good because even a little buff or debuff can work wonders, and the small increases through shards are appropriate.
Any thoughts? If you agree, maybe we could compile a list of UP spells and suggested changes for the devs.