For my next suggestion, I would like to propose that wood furnaces generate smoke, and all smoke carries risk of smoke inhalation which works much like miasma except that it causes death with prolonged exposure.
The smoke should attempt to rise to the highest point available, and should not dissipate until it reaches the outdoors, at which point it would become harmless, much like forest fire smoke. If no escape can be found, it should accumulate up to a maximum density and then begin to fill lower levels until all available space is filled. I suppose this means it should act partly like miasma and partly like an upside-down fluid with only 1/1 depth and no pressure. Since smoke is an undesirable waste product and not useful, I don't think players would mind or notice a more naive implementation than exists currently for fluids.
Thus players could either place wood furnaces indoors with a vent to the outdoors, or simply build the furnace aboveground. This would enhance gameplay by either creating the need for constant, open connection to the outdoors without creating a security hazard, or encouraging the player not to abandon the above world entirely.
There are certain things that can be done in Dwarf Fortress legally but which I find inelegant or unrealistic to the point of feeling like a cheat. Operating wood furnaces indoors with no ventilation is one of those.