In Arcanum, I believe the only real difference in the Healing and Necromancy skill sets was that they used positive and negative energy, thereby reversing the tasks. Positive energy necromancy = heal, negative = harm. Positive energy necromancy = resurrect, negative = creating zombies.

It was cool, and makes more sense to me, since the only difference between necromancy and healing is that necromancy does the same sorts of things for negative effects. They're two sides of the same coin in my books.