So the Witcher has to meditate in order to make potions!!! That is silly and DUMB! That is why I said before that the character of the Witcher has been poorly conceived from the beginning (if that is true). I mean, like what happens, his meta physical body rises and it creates the potions (rhetorical question)???
He is a Witcher with magical and physical powers, yes, and if he needs to meditate to maintain those powers i.e rejuvenate, well, that's great, nothing wrong with that (like sleep or eating to rejuvenate your health in other games).
Potions on the other hand are just based on knowledge and ingredients found in the natural world along with the alchemy tools to create them, so NO meditation should be needed to create potions!! AND no meditation should be needed to drink them!
I like the idea of Armor with X number of potion slots, you could have all kinds of combinations of Armor that have X number of slots as opposed to some other stat increase and the player would need to make a choice as to witch Armor they want, more slots for potions but less stats in other areas or less slots but more stats in other areas - all players choice depending on how they want to play.
As far as using the potions, well, again, you drink a Red Bull now, the affect takes place NOW! How much Red Bull can you drink, well, that would depend on the toxicity of Red Bull (potions) and your ability to survive the toxicity, but it would be your choice and the kind of Stats that you selected as to how much toxicity you can handle.
And if drinking a potion in real time is somehow going to kill you because of a animation (of drinking I guess) than there is something wrong with the how battles are implemented, I mean, it should take what, maybe a second to drink a potion that's all ready to go sitting in one of your slots, on the other hand, I could see myself, getting away from the Monster/whatever for a second or two to be able to grab a potion, open the vile and drink it! And if you don't have that second, than probably you should not be in that battle to begin with, wait till you level up some more.