Let me list a few:
crusade unit balance. It is laugable. The initial army sizes are insanely small for no good reason. With ONLY 3-4 slots to work with, why would you EVER take 10 sorcerers or 4 mages you get? You cannot get more (I’m far into act 3, built every upgrade). Mages for example, use lighting, against which demons are immune. And demons are you main opponent. Useless. There is zero incentive to split troops, since you CAN’T. The slot limit is a crime.
And even better example would be the first choice you have to make - upgrading Footmen.
Regils suggestion makes perfect sense in RL, but not in the game. Shield bearers have no offense and no way to lock an enemy, so they are a waste, despite their tankiness. The enemy will just go around and attack your squishy units. Even if you were to give them the ability to threaten all sorounding squares and to Attack of Opportunity, their damage output is so low it wouldn’t matter. The ONLY time they can actually do their job is when there is a big obstacle on the map. And even that is a maybe - many demons can teleport.
What about Champions? The best trained footmen, in full plate and with greatswords, but low in number? Sounds great on paper, but their AC and HP looks like typos. They are made of tissue paper.
The sheer differences in values, the sheer insanity of them. And it’s similar with most units. One unit has 22 HP, other has 156HP (same tier).
It’s like none of the developers bothered to test it or look it over. Who in their right mind approved this?
utter lack of helmets. Even basic ones. Seriously, add basic helmets to vendors. Add more helmets and buff them, because NO ONE will take +4 inititave on helmet over +4 to CHA/WIS/INT circlet.
armors that actually work and aren’t trash. AC is king. DEX is king. Armor is laughable, because it doesn’t ACTUALLY protect you when you get hit. This was always a problem with pathfinder and D&D - the AC system makes no damn sense for armor. Armor should give you AC (unless enchanted) - it should give you Damage Reduction (flat) or Damage Absorption/Resistance (percentage) or both.
The max dexterity bonus should instead be a dex bonus penalty, not a hard cap.
severe lack of specific weapons/armor. Just add a blacksmith that can forge what we need for a hefty price. Custom ordered weapons/armor.
class balance. All over the place. Far too many classes for no good reason.
unfinished. So many quests/characters seem like cut content.