I think there should be no modification to the heal spell, and that the potions should be removed. Amia was a damn nightmare due to the availability of potions. It removes both the sense of danger, or risk, from virtually anything. If it was modified, I would suggest 10hp per caster level, but casting heAL has its own risk. . Everything tries to hit you, you can be disrupted, etc. Potions are just chug away. I do not like the potions, or modifications to the spell, but hey.. I'll stay frosty.