The reason is simple, but tricky. I thought the same thing first, until I saw that Ice had the highest health, evidently the weakest attacks. They do get higher blades and traps, but shielding, and defense, is their main thing. Life has a lot of tougher spells, because they have lower health. Life doesn't have one spell of damage under ice. Centaur is very powerful, though it could never go up against a Stormzilla. I don't think Centaur is overpowered.
