I'd be interested if they made it so that towns with ironmongers (blacksmiths) could get highter tier armour, like chain maile, if they have a tanner they could get higher tier leather stuff, basically create a supply and demand for arms and armour, then instead of having these facilities create a set income of 200 or what ever, it goes up in times of war and back down to a basic income during peace, (peasents getting plows and tools fixed etc).
The wood worker for example could increase the quantity of shields, bows, xbows and polearms as well as when construction projects are going on generate more income or a boost to construction speed. It would create a more diverse and strategic manner for equipment to be created.
Or even work the building levels into it, so a tier 1 backsmith would produce basic swords and armour, a tier 2 would produce mid level stuff and a tier 3 would make top tier, as well as more, even having chances for higher quality pieces to appear. then from all this caravans could be set to see if it would be profitable to purchess equipment at stocked towns and sell it to towns that are dealing with shortages.
obviously towns without these buildings would still have some equipment however it would just be really basic stuff.