I've alsways wonder why there are offensive potions e.g http://www.uesp.net/wiki/Morrowind:Potions#Illusion or defensive potions e.g http://www.uesp.net/wiki/Morrowind:Potions#Restoration in vanilla, and to me both these potions are almost impossible to use properly.

It doesn't make sense to drop a Potion of Paralyze on yourself, but the Potion of Cure Paralyzation is different since you cannot drink anything in reality. So how can you cure paralyzation if you're paralyzed?

Of course you can cure yourself if you're playing a game, but these potions aren't immersive in-game IMO.

So I had an idea if similar potions of those potions I mention could be modified via a script(s) if it's feasible.

I know there is a Reguard Healer Penald in the http://www.uesp.net/wiki/Morrowind:Mannammu cave just outside of Pelagiad and he possess a Potion of Paralyze I believe, so every time I enter this cave regardless if I do the Fighter's Guild quest or not he always rush towards me with his hands ready to cast a spell. Now, how can that be possible when even I can't figure it out of how to do the same thing as he does in-game.

One of the features of the mod I've been working on is the addition of poison crafting. It lets you use any offensive potion in combat, either by throwing them and having the potion explode on your target, or by coating your weapon with the poison and inflicting the negative effects on whomever you attack. Works with any potion (vanilla, modded, or self-made) and with any weapon as well. The scripting is mostly done, but after trying it out I realized it's way too easy to make uber poisons so I need to rebalance vanilla's ingredients in the CS. (The scripting involved in this is definitely not trivial)