The Heroes Round Table

What about artifacts that make creatures stronger, such as an ammo cart for example, to give all creatures in the army infinite ammo until the hero drops dead?

Perhaps to fix the endgame economy, creature growth could scale based on how much time has passed in game. For example, base creature growth could increase by 50% for every month that has passed (obviously have a rolling increase rather than a sudden jump). This additional time based creature growth...