Since there is no real enthusiasm for improving alchemy skill to encompass more recipes, I had another idea.
What if chars with alchemy had a chance to spawn alchemy shops, which would be variations of potion shops that contained only ingredients required on the list of recipes?
The prices could be set accordingly high, spawn rate is already low but perhaps it could be slightly higher than any other average shop - assuming the PC in question has the skill.
There is the issue of restock and this being perhaps too OP but it's still a heavily luck-reliant feature. Anyway, with luck we're talking about getting ingredients for 2, perhaps 3 PoGA, that's it.
With alchemy shops, the skill would find more use and the change would at least partially satisfy a group of people (including myself) that feel non-offensive alchemy is lacking in complexity and continuous usefulness.
One such shop could even be guaranteed somewhere in the game, for a char with the skill or one that obtained it via wish or education items and still has some unexplored levels to generate.
With such shops, there could be increased chance to get your hands on some potions of youth and longevity in sufficient quantity to revert age related issues after encountering ghosts.
It would certainly make me wanna consider playing a human or an orc once every year instead of... well, never.
There is already a precedent for fixed items in shops - amulet of resurrection for example.
Thus, not much work would be required.