I don't want the game to be a space western or something like that i just find the basic things necessary as the game has a kind of western feel.
So here is a few ideas, hope you enjoy them.
-Six shooter (hand gun ofcourse)
-Half door (like a saloon door, could make the rooms feel more open in the more temperate regions)
-Whiskey (or just strong alcohol, which is would obviosuly be less healthy)
-Bar tables (for more rich towns, would be sweet if you could get your prisoner to be a bartender for a trade of better livinig conditions)
-Cow herd AI (i don't know if this is asking for too much, but taking cows out to pasture instead of just feeding them would be so sick.)
-Winchester repeater (the carbine rifle thingy)
-Horses (now don't get me wrong i don't want to ride them around my area, but finding them, breaking them and then selling them would be a cool way to make money! could also be a good animal for traveling to other regions)
You might want to look for a western mod. But for gameplay purposes nearly all of your requests are already filled.
We got a pistol for the revolver
We got the Survival rifle for the lever-action
We got something like 10 different drugs, and we don't really need another drug that just acts as "That drug but stronger"
Tables are Tables. Bartenders don't make sense in a communal society where you can just take as much beer as you want from the fridge and no one will stop you. See the Dwarf Fortress economy update to learn how that goes.
Horses for cargo are fulfilled by pack animals of all types including cows. If we get transportation to make pawn caravans faster, it'd going to be for more than animals when that update comes and will likely include trucks, sleds, carts, and possibly even assault vehicles.
Half Door? Just left click the door and select "hold open". My entire colony (sans refrigerator) uses stone interior doors because I see no reason not to have the doors open, and they can be closed during a raid.
Herd AI: Build an Allowed Animal Zone outside the colony where there's lots of grass. Now switch between the in-colony area and the outside area. Believe it or not the Cows (and chickens I think) will eat the grass outside for sustenance. No hay required! Just remember to switch the zone every couple days to let the grass grow back.