I just realized some more uses for the currently-being-worked-on poisons. It's a big wall of text so there's a tldr at the bottom.
Alcohols (and later, drugs) should be counted as a weak poison effect. One benefit would be that this allows us to customize what creatures are resistant to the effects of drugs and alcohol. So dwarves gain no effects from alcohol, but they might have to have a pseudo-poison entry in their raws to show the effects of alcohol deprivation if it ever gains effects beyond unhappy thoughts and slow working (for instance, they could occasionally get dizzy and not be able to walk straight or they could get slowed down in all actions instead of just working).
Humans would have a decent tolerance to alcohol, though it would make them temporarily dizzy and dumb, meaning it would penalize their... *looks up the list of new attributes*... oh damn, this penalizes lots of things. Instead of listing out all the skills (it would penalize almost all of the soul-based ones to some degree), I'll say that mostly it would make them clumsy and dumb, though they'd keep their musicality because everyone likes drinking songs. The US national anthem wouldn't be the same without them. For long-term effects (you see these after a lifetime of alcoholism) alcohol would deal very light brain and liver damage when consumed in large enough amounts.
Goblins would have a higher-than-usual resistance against intoxication and liver damage, but normal resistance against brain damage. I could see kobolds having low resistance against the temporary effects but high resistance against the long-term effects. Or maybe they wouldn't, since they mostly would be resistant to the types of poison bugs use and I really don't think those are similar to alcohol. I like using scorpions for these insect poison examples, but I can't seem to find what makes up scorpion poison and why it's dangerous. Any entomologists want to help me out here? I also can't find out exactly how alcohol effects you on a cellular level, as people only seem interested in the effects. Any biologists with some knowledge of chemistry and much knowledge of near-useless biology facts?
This could also pave the way for new drinks, though they wouldn't be brewed drinks since alcohol is alcohol no matter what the source of the sugar is. Maybe a sugary, sweet drink that gives you temporary infertility or something like that. Unique stuff. Everyone likes unique stuff.
Another benefit from this is that there would force more types of poison, and therefore more fun effects to be around. Imagine a snake that defeated its opponents by injecting concentrated alcohol directly into their bloodstream. In the short run this would cause intense dizziness, vomiting, and all the other effects of drunkenness but more extreme. In the long run, it would damage their brain and liver. The trick to defeating these would be getting a dwarf to fight it, and some dwarves might even keep some as pets.
That's one option, though we could have something else like a mutant tobacco plant that released concentrated carcinogenic toxins into the air when you bump into it. Or a trippy giant scorpion that had LSD in place of the normal scorpion toxins (which, I believe, cause paralysis).
I just realized that this would work even better if poisons were instead turned into a subset of a general Substances raw. Therefore we could have substances with positive and negative effects, like steroids tricking your body into thinking you have an overabundance of hormones. And tobacco could cause slight relaxation (I hear that's the main reason to smoke) along with its negative effects (most of which are long-term), while marijuana would have more potent relaxation effects and might give a small boost to creativity while making the user more hungry (munchies) and would also last longer.
You wouldn't want your soldiers smoking pot and then trying to hug the goblins (your wrestlers already hug goblins, but dwarves on pot wouldn't hug them nearly as "effecively"), but you might be fine with your master engraver smoking a joint and gaining inspiration for a far out, psychedelic engraving.
You could make your soldiers take PCP to go all berserker. They'd become immune to pain and maybe get a strength bonus because they're not holding back, but they'd think they had superpowers and therefore do some very stupid things like ignore your orders to attack from the rear in favor of charging straight into several trolls and a few goblin mace lords.
Oh my, that was a lot to read.
TL;DR: Alcohol and drugs should be weak poisons, poison effects should be created for them should be usable by creatures, poisons should be turned into general substances and allow positive effects as well as negative.