I voted for a new addiction system, maybe one where withdraw starts off strong, gets stronger after a few days, then weakens over the course of a few weeks (depends on the drug) then finally dies out.
I like that idea, but I think that when the stat penalties (or whatever other withdrawal effects) are bad, they're
really bad. That would make people stop and consider finding a cure, rather than just waiting it out every time.
Also, maybe you could only be cured by certain people, to avoid players just stocking up on "cure addiction" potions? And no "cure addiction" spells I reckon.