I'm still unsure about this new system. On the one hand, I absolutely hate mindless grinding for material, it adds nothing for me in the game. If this new system makes acquiring each new material an adventure in itself, that would make the process much deeper and more entertaining. If they also make those resources very limited, meaning you'd need to be very careful when choosing which potions to have in your arsenal and how much to spend on upgrades, that would also be good and require the player to put more thought into it.
On the other hand, it means that consumables essentially get removed. You no longer have the challenge of balancing out how much you want to spend for potions, how much for bombs, how many of each potion/bomb to make instead of others etc. That's the whole point of consumables and something that the new system strips away. You could also argue that a limited supply of potions/bombs in the game provides a bigger challenge and provides another layer - supply management. And, in theory, that would be a strong argument. The problem is, that was never the case in TW1 or TW2. You always had more than enough resources at your disposal - too many, even.
The question then becomes, what do the developers aim to achieve. What I've gathered from these interviews, and from the alchemy systems in the previous titles, is that the devs don't want to limit those resources. They don't want to limit our supply, as those items (potions in particular) are tools that witchers use all the time. The new system pushes that idea even further, trying to treat alchemy items as buffs rather than consumables, because that's how they envision them - they want the player to be using them all the time, not just on occasion. 'Cause that's what witchers do.
So, ultimately, I still need to see it in action before I can really form an informed opinion on the matter. There are too many uncertainties about the system: how rare ingredients are, how they are acquired etc.