I kind of like the mana lack, and it's rather balanced. We can't have everyone always having mana, then people would be spamming too much stun, etc! Stun, whack, run away, stun, whack, run away...
We need people lacking mana to give other players a -chance-. We don't want this turning into a WoW wannabe, now. "I has mana, i keel u"