I played only three games so far (chalenging, hard and difficulty above whatever its called) and I steamrolled them all. And here are the issues I had with them.
1. Attack/defense
Current system allows stacking of those indefinitely which eventually turned my sovereign into some kind of natural disaster sweeping everything on its path.
My suggestion is to put a cap on attack and defense for certain type of unit. For example humanoids (sovereign included) should have much lower attack cap than, lets say, ogres.
2. Summoning monsters
Simply put - way too powerful considering how early you can have them.
3. Confusion spell
My god!!! This spell turns every game's difficulty to cakewalk. It should have check every turn for the duration and it should definitely break on damage.
4. Global spells
What is with that? I literally spammed earthquake the other day. I won't suggest anything here cause I find concept of global spells in (ye, I'll mention it too) Age of Wonders so good that you only need to check it out.
5. Tech
In my very first game I researched three trees (magic, civic, diplomacy) to the maximum. Researching goes waaaaaaaay to quickly. In GalCiv you do the research at the cost of... something. Here research just comes. And it comes fast. Right now I don't care what I research because I know that I'll get whatever I need from other trees in just few turns.
6. Children
At the moment goal is to get married as soon as possible and start spamming children that will summon monsters. Literally you can f*** your way to victory. Am I the only one who sees that there is something wrong in this concept?
7. Mana regeneration in tactical
It needs to go. Put your children on mounts and abuse this to hell! There is no reason not to end any combat without full mana like this.
8. First move
Order of movement should be determined by unit's combat speed for each unit. Like this, attacker's advantage is just gamebreaking.
That's it for now. Thank you for reading. I really hope that we won't talk about this game in terms of it had potential forever.