I remember back in Morrowind where most shops wouldn't trade with you if you had skooma/moon sugar on you. I miss that.
Sometimes that annoyed me, because they magically knew you had the stuff.
Overconsumption of Skooma in Morrowind nerfed your intelligence, essentially permanently. They could bring that back.
well I liked how in FONV you could get addicted, then need to get healed of addiction or keep consuming. I would have liked that even more.
I think a combination where addiction worked similiarly to vampirism, the further you descend into it the less likeable by the general populace you are and in the later stages you have trouble renting beds at inns, and lots of merchants turn you away etc..