Healing via magery, spirit speak, chiv, or bandies require investment in skill points. Healing by pots require no points. I guess they could have always made it so in order to get full use of the pot you had to have alchemy. No alchemy, then greater pot heals the same as a lesser heal. At 50 alchemy, then normal heal pot, and at GM then you get the full greater heal. Wearing enhanced pot items would only give a percentage increase. So say that you had no alchemy and the lesser heal pot only healed 10 points and you had 50% enhanced pot on char then the total heal would be 15 points.