But still...the enhancements are not unlimited.
When you have created all the superior potions, you have a lot of herbs around which are pratically useless.
No what I mean is that they actually require you to have all the ingredients EACH TIME you want to refill your SUPERIOR potions, instead of only needing it the first time. That would be a way to make the system more complex, giving beginners BASE potions so they never need to farm for any potions after the first time and can easily use them, always having them ready, and to say "hey for you who are more into alchemy, here are 2 or 3 different upgrades for each potion, you need a formula for an upgrade obviously, or you can experiment. Now for each upgrade a new (more rare) ingredient is needed, but you need to collect this ingredients (and all others) EVERY time that you want to make such an advanced potion, it doesn't refill". That would be a good idea I think, and a way to make it still required to collect ingredients, IF you want the best potions.
Look, the base problem here is:
1. I don't like auto-refilling potions, it basically makes them a "buff" skill (like in an MMO) that you can use any time and have a number of uses until you need to "recharge".
2. I don't like not having to collect at least SOME ingredients, even if it's just 1/6 of what you originally had to collect. It's not the quantity of collected herbs, it's the actual procedure of collecting them and brewing the potions that makes for a kind of strangely satisfying roleplay experience for me
3. To have SO MANY herbs around is just a waste of development and memory resources if you can't use them. And if you only have to collect once and then don't need ingredients anymore you basically don't need them. Sure, upgrades, but even those are done after some time.
The point is, I can simply not imagine why in the WORLD CDPR would create SO MANY herbs all around the place if you only had to use them ONCE for each potion. So either they plan on letting you collect hundreds of herbs of one type for each potion or upgrade, or they are wasting resources.
OR - and that is the clever thought-process (again, maybe I'm thinking top complicated but.... - they have a system where the BASE potions always refill, but for any UPGRADED/SUPERIOR version of the potions you'll need to collect all ingredients. That would also make sense in terms of the the immersion/lore-explanation of "stretching the potion". You can't make a superior potion by stretching it with alcohol, you might be able to make a base one though and keep it's effect for some time. That makes sense in a way, at least on the surface, if you don't go deeper and overlook the effects time would have on the potion stretching process. Which is okay by me. It would also have the advantage of satisfying both beginners and alchemy-lovers.