Contrarian take, but I don't think TW1's Alchemy system is meaningful at all, regardless of difficulty. Swallow alone will carry you through any fight in the game. The system itself is certainly deep having a wide variety of recipes and it's thematic, making use of real hermetic terminology, however it's completely wasted on the lack of challenge that even the most unusual enemies present. Most of their routines are extremely basic and copypasta'd from one to the other. Drowner = Ghoul = Fleder etc. Couple of unique abilities, none of them warranting special care or treatment, for the most part identical barring HP pools.
Off the top of my head, Black Blood is a good example of fluff. Vampire bites you, it dies instantly. Cool idea, problem is it will never bite you, it will be dead long before that happens and even if it does get lucky, who cares when a bite does like 20? damage. Another one, a particular recipe, can't remember the name, allows you to see invisible enemies. Cool idea, but there are zero invisible enemies in the game. Shame really. Many others just buff attack or damage or stamina and are basically pointless, shaving maybe a few seconds off of combat.
Act 1 is the only part of this game that poses any sort of challenge due to the lack of a silver sword and the recipes you find there are minimal. Throughout the game reagents are way, way too common, just about every foe drops them and herbs respawn whenever you zone. The player can also hold way too many of them. This destroys the resource management aspect that the game could have easily provided. Additionally, Geralt can carry hundreds of bottles of booze and an entire pantry's worth of food, yet can't carry more than 3 swords? A half-hearted commitment to realistic inventory might as well not have been bothered with. Minimally, swallow potions should have been much harder to make than they were. If I were a dev, I'd have severely restricted the ingredient drops for those, but the biggest problem is still the lack of combat difficulty and dangerous abilities unique to enemy types that could reliably overcome the regen.