Well, it was solid enough for me and solid enough to not be tampered with, as far as I'm concerned. "Never touch a running system".
And from what I could gather, it actually seems to have a lot to do with newcomers. Or is there another reason why CD Projekt Red would cut down on the (repeated) potion-brewing part of the system and replace it with auto-refilling potions? Most of the people who played the previous games surely wouldn't mind clicking that Create Potion button a couple of times in the third installment of the Witcher as well?
If the opposite is the case then
How solid the system was or not yeah that's subjective, to me it was ok, but like i said, poorly balanced. But still potions weren't important or crucial, unless you set TW2 at max difficulty, which means the game kind of failed then, if potion are such an important part of witchers, yet it doesn't play its role properly in any difficulty but the top ones. And in TW1 only with FCR were they really important, or against the koschley and javed.
And the newcomers is not the reason for this change, at least not if you believe the REDs. Its not about how easy it is to create portions or not, or how tiring, its about players not using them often enough, because they are either too precious so players save them, or because they make you OP in most battles except bosses and such. Players like me for example, that love high difficulty and challenge that's both strategically based and reflex based, will often push themselves into beating challenges in the most "effective" manner, so that means saving potions for big fights, you know, kind of like in Survival Horror games you save up your powerful ammo/gun, but in this case they want potions in TW3 to be very relevant and a good choice for many battles, to integrate it more with normal gameplay moments.. Just listen to the interview with Konrad that's here around the forums, he is sitting in a table with a bald guy I think.
Im not siding against or in favor, just to make it clear, im trying to explain what the devs said.