[Sandman]

National troops should be upgradeable. At the moment they derive rather less benefit from magic research than mages, summons and SCs.

Suggestion: Castable perma-upgrades: These are a set of spells which confer a permanent bonus on mundane humans or similar. Fire resistance, demon blood, lycanthropy, undeath, etc. The key feature? Only one upgrade per unit - they don't stack. Even so, it gives you a lot of options to play with when it comes to national troops.