Adom is not every single rougelike. If all other games of this genre lack a certain feature, that does not make it a must or a standard. It simply means their creators failed to find a way to properly balance them.
Most RPGs are simplified because they focus more on other game elements that require significant manpower to program and successfully implement - graphics, physics, voice acting, music, sound in general...
Adom doesn't have those elements so its strength is immersion and complexity. Why on earth is there a feature where you have to eat things that satiate you, you can bless or curse your food, eat corpses that provide multitude of game changing elements, bother with rotting, have an entire character class that has skills related to changing corpses into food rations, food preservation and all the other stuff, but avoid something as simple and obvious as empty vials left after drinking potions, and in case of my RFE - ONLY potions of water? It doesn't make sense.
I'd dare going as far as to say that half the programming and features behind the complex food/eating/starvation system are useless and only help in complicating the game in areas where no complication is needed or justified.
Don't even tell me about adherence to genre because I don't buy it.
Mind you, there would be little inventory clutter since for example b/u/c status would be carried over from the previous status of the potion.
Secondly, considering that random empty vial drop could be set to 20% that of potions of water and you could only refill bottles that you have used up yourself or found, it wouldn't be op, no more than sacrificing 10k gold to raise piety and dropping a heap of 972471 cursed potions of water on an altar to get them all blessed for no cost.
From the lore perspective it would absolutely make sense, definitely more than being able to dip a large object such as a full plate mail, a heap of swords or a pair of boots/gloves and yet only one potion of gain attribute instead of 4 or 10 that would correspond in size to previously mentioned items (not necessarily PoGA but one specific attribute, it wouldn't be too OP).