I think Zombie needs to be "re-imagined". As it stands now, you only heal for a small amount per turn, and any further healing on that turn requires that you expend AP points moving around in it. That simply is not worth giving up healing spells,potions, etc, for.
It would be worth it, if zombie allowed the poison damage you do to enemies to heal you, but at thee expense of giving up all other avenues of healing, and made moving during combat cost more AP, and made you take a certain % of more damage when you take damage. You're basically a zombie.You're slower and your rotten flesh/muscle makes you weaker.