I can completely understand if people are sceptical but any other choice than either "Yes" as a response of it being better than previous games or "Need to see it in action" as a response of it sounding dodgy, are either dumb and or illogical.
Witcher 1 had a rather bad potion system, drinking potion in the middle of the fight really screwed up the flow of the combat and if implemented like in the Witcher 1, we will either feature the same stupid thing of Geralt standing still getting chopped while chugging or him running away like a headless chicken. Witcher 1 had nice alchemy system with side substances (all be it Geralt running around with a butt ton of liquor was a bit dumbfounded... Yes you can have a drinking system but you don't need useless tat for "realism" when we are talking about alchemy), not however how the potion was consumed in combat and people wanting it like in the Witcher 1 either have bad memory or confuse this with the alchemy system.
The alchemy system in Witcher 2 while being more close to the lore got criticized by gamers/journalists cause it was problematic to ever know when to consume a potion beforehand unless you've actually played the game before and knew each situation. This is bad game design and CD RED fixed (will fix) this with Witcher 3 (Game play is always more important than lore, cause these are video games, the whole purpose with a game over a book is the players possibility to interact).
This if anything is a step in the right direction which makes preparation beforehand still true to the lore but also doesn't disrupt the "flow" with combat. I would also like to stress that CD RED have talked about the potion system as being divided to, Basic potions you consume before hand, and support potions you consume in combat to sort of tackle both of these issues and also sort of give player a pat on the shoulder saying "See we have both W1 and W2 potion system, now please don't hate us". Whether Witcher 3 will feature both these features as well as the metabolism is something we'll see, though I wouldn't be completely surprised if they've actually removed the "release effect from metabolism" seeing as that is by now quite a old article and we are still 8 months from release.