Alright some observations I have made in the past few weeks as I have taken a small step back from my overly ambitious armor mod.
1# Healing is far to weak in general. Unless you get lucky you can heal very effectively more than one person at a time if that person is taking a lot of damage. This is a problem with other spells but healing it is a direct problem if you want a healer unit. Basically the spells just fail to scale.
2# Boss damage is far too low. What I mean by bosses I mean Dragons/Elemental Lords/Quest Bosses/Dungeon Bosses. These fights are supposed to be epic. These units are supposed to be almost gods, shrink/blind should NEVER work on them.
3# Early on end bosses have far too few hp. At turn 100 with a lucky set of archers from a quest I almost killed a whole wildlands with just my sov and another champ. I would have finished it but torrax attacked me before I could save up a little more mana. While their hp looks epic at turn 1 by the time you hit turn 200-300 they look only a little tough if you have any kind of high damage trained units.
4# Trained units damage is exponentially out of control at the end of game. You can literally have a group of 7 Fully armored Kinghts running around with 30 Damage swords with buffs from training and spells hitting around damage 50. While a single unit at damage 50 is tough a group of 7 means you get seven chances to hit at that point compared to one.
5# Items get too many discounts making the increased cost of production null and void by end game. Those damage 30 swords previously mentioned cost next to nothing in training cost if you have a weaponsmith and the underforge at a level 5 fortress city. This marginalizes your champions/heroes.
Recommendations
1# Scale the spells with level. For each tier set a maximum amount they can scale. So for tier 1 spells they increase every 5 levels. Also have spell +% to damage stack onto healing effect spells. Currently they do not.
2# I would recommend making all "Boss" units effectively magic immune except by someone while has a LOT of points into spell mastery and by a lot I mean like 150+ points. While they can still take damage from elemental damage this removes exploitive crippling spells from removing the true challenge these units are supposed to be.
3# I would recommend doubling or tripling their hp totals to make the fights hard. I know that when two dragons are fought together the fight is insane but a single dragon can be beaten fairly easy. Make it that dragons have dragonlings with them since after all they are guarding a dragon roost, make them have young dragons with them to fight.
4# This will likely get me yelled at, lower across the board all trained units accessible damage weapons. It is a simple numbers game when trained units have access to the same gear a sov/champ gets. They have more strikes even if slightly weaker because of lack of traits.
5# This will likely also get me yelled at, lower across the board all discount abilities for trained units. If you want to deck out a trained unit in the final end game gear that's available to them that's great, but it should not take just as long to train them as spear weilding leather wearing units when you apply their armor/weapon/training discounts from improvements.
My 2 Copper