If you could change one rule to tweak things in your favor without going overboard, what would it be and why?
Let's try to keep this constructive.
Here's what I would change:
Koldun Lord's Elite Cadre is changed to [Greylord].
This would allow Valachev, and the Greylord Escort to take advantage of Battle Wizard. This wouldn't be overpowered but could allow for some fun combos as your Doom Reavers could charge and the Escort might still get a Frostbite off. Alternatively, Valachev could charge with his unit and Zephyr if he managed to kill something. Obviously, it wouldn't do anything for Zerkova. But the Greylord Outriders...