Hi i want suggest to introduce for every faction a new strutture, mercenary guild that let reclutate odgs of war units.
This mercenary corp have toons of option and unit
example Asarnil the Dragonlord , a powerfull hero at service of empire
Birdmen_of_Catrazza, Flying unit that use leonardo wings
The Cursed Company, heavy armored undeads
Golgfag's Ogres, armored ogres
The strutture can be upgrade 3 times and let us to access to unit compatible with race (so no chaos warriors o undeads for empire or greenskin for dwarfs