It seems to me that the spell system could use some upgrades and variety. Particularly the Life/Death path. For example, why not a Shadow path, unlocked by having both Life and Death Apprentice that provides some of both Life and Death path spells, as well as its own unique spells? Further, shouldn't Life spellcasters have accesss to spells that cure lingering injuries for champions, rather than having to find potions to do it? Also, shouldn't Life spellcasters have spells that disrupt the magic that animates the undead, kind of like a Sunder spell that works on them? Lastly, it would be nice if someone should manage to get all four elemental spell books as Archmages that it unlocked a High Mage spell tree with its own spells of power beyond that found in other spells, and requiring ownership of at least 1 shard of certain types to cast?
As an aside, it would be nice to be able to create your own items and magic items, with an improvement being required for normal item creation, and this improvement and a spell required to create magic items. The former requires gold and iron, the latter requires gold, iron, and mana. A similar system to the unit design mechanism could work here.
Lastly, it's rather silly to have to have a race trait or scroll to retreat from battle. A better mechanic would be for those without that treat retreating to kill any trained units 50% of the time, and to reduce the current hit points of Champions by 50% and Soverigns by 25%.
Just some thoughts. Comments? Ideas?