Well yeah, but like I said, even hard stims with serious side effects are a marked improvement over arsenic. How frosty are your guards going to be with chronic diarrhea?
East India style drug trading would be an interesting mechanic, as would gifting infected blankets from the plague quarantine. However, I wonder if they really fit the tone of DF.
As for the rubber bouncing between Ecstatic and Depressed, I'd like to see those two states further apart. Many of my drarves hover above ecstatic, but can still drop down to unhappy or miserable over a fairly minor thing. I often find myself wondering how ecstatic my ecstatic dwarf is, and counting up his happy and unhappy thoughts to make a rough estimate myself. Making the ranges wider, so that some currently ecstatic dwarves become quite consent, and a small number of unhappy dwarves read as miserable, would make it easier to tell how close to the edge a specific dwarf is.
Right now, anything other than ecstatic is "unsafe" and ecstatic is "possibly safe, but how would you know?" It doesn't make for a particularly useful gauge of dwarven sanity.
Also, why do dwarves have to freak out if they lose a loved one? People aren't normally happy about losing loved ones, but most people can cope with the loss, without torturing animals. Maybe that's just dwarves, but I'd like to see more responses to sadness than violence. Moping is a good start, along with stealing and career changes (No more carving wood for the man! Life's too short for that! I'm going to follow my dream and become an architect!).