Instead, build them for their versatility because their heal and shield spells are really strong thanks to the int scaling and you can use spell scrolls while the actual spell is on cool down too.
I have not noticed any tips about heal and shield spells scaling with int. Are you sure?
I should have worded it better and say int along with skill tree scaling with the tree for shield/heal and int for spell scroll and other spell. Heal/shield don't scale directly with int.
Some of the tooltips are bugged right now though so evne if it appears to have really low value, like "Mending armor", the bonus is applied once you actually use it. It currently gives me 26 armor per round (and on cast) although it says 21.
