A very good review. I think that only the Cyseal map has been heavily playtested, because the story has more flaws in the following maps and the combat is more unbalanced.
A few suggestions:
Glass Cannon: Maximum AP +4, Start AP +4, Recovery AP +2 and Vitality -25%
Leech: The character heals (damage X 0.25) points with every physical melee or ranged attack
Resistances: Should have a maximum of 75%
Magical skills (Air, ...): Every 3 points of intelligence should reduce the cooldown and not every 2 points
Physical skills (Scoundrel, ...): Should have a cooldown reduction, too, that is based on dexterity or strength
Ranged weapons: Bow 3 AP and not 4, Crossbow 5 AP and not 6
Tenebrium skill: Should be removed and replaced by a talent
