Uh, I think Zombie has a major downside in that you require poison pools everywhere to heal. That may be great for certain situations, but terrible in others, like fighting fire-based enemies. Plus, I assume there will be a lot fewer undead enemies after Act 1. (If there are loads of undead still, then poison damage will be pretty terrible.)
Agreed. However, one can easily learn the poison dart spell which allows to create poison surfaces.
