I hate potions because it turns the game into a clickfest. You either don't use them and are at a disadvantage, or use them heavily, and suffer through the tedium. And you have a ton of these drugs, because why not? This is especially fine for weak, long-duration potions (you need to drink several of them, each soldier, each mission). Please don't make this into Neverwinter Nights. If you want minor buffs/debuffs lasting for several turns, why not make the life easier and just build them into an armor suit, to last whole battle?
Having said that... most of these effects are working in OXCE already. You can't improve stats like firing, but you can buff/debuff any temp stat (Morale/Energy/Health/TUs), even way above the maximum (it will get trimmed the next turn, though). You can also damage or buff armor. Or inflict any kind of damage upon yourself while using an item. You need to go through a fake weapon not a med-kit, though. This is what I like, you won't do it often because it's one-off, so it's not tedious, and it involves an actual decision.