[wolfing]

what you saw in the tutorial was the 'knight' unit that you thought was your hero. It's 2 different things. Your hero is an out-of-combat entity that provides abilities/bonuses to all your units, and also can cast spells once per round (even if you're a warrior). Warrior hero's units do more damage and resist more damage than the Mage's units, but the mage can cast more and more powerful spells. If you think the mage hero is more powerful than the warrior and the paladin, well that's a balancing thing, nothing to do with the game being incomplete.
Your hero can wear items, and those items add to the units in the battlefield (if the item adds +2 defense, then each unit in your army has +2 defense).