I don't think that they'll try and add in changes to this (or changes to bow/crossbow balance) in Original Sin on top of the balance/difficulty megapatch they're doing. However, this discussion could possibly be useful for Larian's future RPG's. So I'll continue it anyway.
Just because it was done a certain way in D&D means it should be done the same way in D:OS. They are different systems.
I don't think potion use should provoke AoO for balance reasons. If you are wounded with an enemy close to you, but you can't move away, you can't cast any attack spells, you can't cast a healing spell and you can't even drink a potion, what exactly CAN you do to defend yourself?
(Most mages probably have few touch spells, since few spells like that exist, plus they usually prefer to attack from range anyway.)
