Playing the guardian sov, random normal map.
Bugs:
- I could not get the spell beautify land to work on any tile
- the skill drain life (Naphaz) says " .. steals 3hp per level from the target enemy". In my game he is level 6, and does 7 damage with this skill (3 if resisted).
- i havent found ANY bows in my games. Nor a recipe for a better bow than the starting recipe. Maybe i am extremly unlucky, but in my last game i found a pyre brand, a sovereign sword, 2 serrated broadswords. Makes my ranger a sad panda 
- sometimes the sound gets weird (proably looses the 5.1). Restarting fixes this.
- tireless march can be cast repeatetly, description says only at one at a time.
- the sovereign skill revive lands should unlock "revive land", but places the spell enhance land in you spellbook (turns grasslands into fertile land), which is different from the description in the Sovereign skill tree. This new spell can only be cast on shadow land though, where it places 2 food icons on it. Casting it put my mana from 66 to -61 instead of deducting the advertised 64 mana. Casting it in a city controlled area it does not increase the food in the city.
- The spell desolation at the end of a skill tree branch in the guardian skill tree is quite underwhelming. whats the point of the spell? Crippling yourself?
- the game crashed one time loading an autosave, debug.err is here.
Suggestions:
with some heroes you find on the map you dont have to fight to recruit them to your cause, which is really nice. Its not so much fun to find - say keplin the mage - with a scout and you know you need 40+ turns just to get there with your army if you dropped doing whatever you had planned for them.
I suggest you could make them offer to join you without a fight (like Naphaz the Warlord) and tie the cost to the doom or threat counter. This way you still have to decide if its worth freeing them but have an option to play with them right away.