what if we attached the amount of summons allowed to the lvl & schools they come from
lvl 3 fire/lvl 2 earth mage could have:
three lvl 1 fire summons + two lvl 2 fire summons + one lvl 3 fire summon
two lvl 1 earth summons + 1 lvl 2 earth summon
edit: upkeep could be the same: 1 mana for lvl 1 summons, 2 for lvl 2 & so on?
so a lvl 5 fire mage could have:
One lvl 5 fire summon at 5 mana upkeep +
Two lvl 4 fire summons at 4 mana upkeep each +
Three lvl 3 fire summons at 3 mana upkeep each +
Four lvl 2 fire summons at 2 mana upkeep each +
Five lvl 1 fire summons at 1 mana upkeep each +
This would allow for an actual summoned army