I thought that the drinking animation was too quick in TW1. Geralt would magically pull out the potion from his massive inventory without even hesitating to look for it, not have to pull off the top of the potion bottle and just chug it and toss it. If they allow mid-combat potion drinking then depending on how much you have on you, Geralt should have to take a few seconds to pick out the item and then pull the top off (like in TW2) then drink it. Also if you get attacked during this process, you drop the potion (if you've already grabbed it) and drop it. If you're in the process of drinking it, then the duration that the potion lasts should be diminished since you didn't finish it all.