I think you'd have to do a few things to level it out
make the progression in levels equal for the wiz/apprentice and the heretor /warden.
limit the warbands like the GA crew, 4 specialists and 4 regular soldiers
or use the same soldier types for both sides (GA crew arent as strong as the FG crew)
200 gold to go back and re hire dead specialists,
no just buying magic weapons.
introduce embed magic to the heritors band or loose it for the wizard,
But I must admit it would be a fun game to try out
Roger