Played the game on hard, the sheer amount of things you can do turned the game into a cakewalk for me.
One game is probably not the optimal testing, but it seemed easier than going Warrior, which previously was the easiest.
Haste, Curse, Flame Wave seem to be the most important spells
Soulburning seemed to be broken- it just sacrificed my unit without doing any damage. If that spell had worked, I could have just sacced units and killed the SK.