@beardalaxy
Welcome to the world of game balancing.
It's not possible. Either all classes are the same, or they will be imbalanced. In WoW, I literally run around a field, collecting about 30 minions to strike at once. They were strong enough to kill me with 2, but I had enough slowdown, that killing 30 was just as possible as killing 1.
I wish I had better news, but the only way of stabilizing the leveling speed are daily soft XP caps, also known as dailies and well rested bonus.