'Dwarfyness' is used as an arguement for nearly any sort of destructive, obscene, ridiculously complex and bloody-minded gameplay pursuit. From hydraulic cannons to executing the king because he mandates crystal glass goblets, players view these temporary blinks of sanity as 'dwarfy'. However players are never forced to construct magma moats, cook *dwarven ale roasts*, house the entire noble class in one room with an artifact gold statue, or otherwise engage in 'dwarfyness'. 'Dwarfyness' is optional.
If you want to call recreational drugs 'dwarfy', then that's a very good arguement to keep them optional. Players who prefer their dwarves to be 'dwarven' and take the dwarves as serious, hardworking, grim little hardasses will appreciate this. Remember, my point of view is not to keep you from what you want, but to keep what I want that already exists.
It makes sense that Dwarven priests and their [RELIGION_SPHERE:FIRE] would be drawn to burning plants within their mountain halls, where the smoke would build up and lo, Armok would show them the plant's inner magic...
Which, just so all is clear, amounts to smoking tobacco and discovering the plants inner magic of an addictive stimulant. Which I am totally for. Dwarves getting addicted to tobacco smoking and being happy from it but the player forced to keep up with demand sounds like fun as well as Fun. I've seen enough humans tantrum when they couldn't get a pack. Logically with pipe-smoking comes a generic 'tobacco' smokable plant, which will lend the nessicary tokens and values to mod in whatever you like. Perhaps opium temporarily gives dwarves [NOPAIN]. Maybe Berserk-Weed gives them [NOFEAR]. Have fun modding it up, I say.
So long as players can keep a fort without drugs, I have no problem with players having a fort with drugs. I just do not want to see it handled the same way alcohol is; nearly mandatory for a vanilla fort. So keep it optional, preferably switched off in the .init right from the start or non-existant until ordinary tobacco-smoking mechanics are modded around.