Siege crafts should be a late-game weapon with the primary function of bonus damage to buildings (houses, storage, towers) and crowd control.
Each would require different resources, such as catapults or trebuchets needing wood, leather, and iron. Meanwhile, cannons or mortars would need stone and metal.
Cultures could affect their production or prioritization such as:
Dwarves, bandits, humans, etc., could build more cannons.
Orcs, wolves, and rhinos could build more catapults or trebuchets.
And elves, monkeys, and cats would build more hwachas.
I can see two ways this could happen:
We already have towers. I could see it where a new "siege crafter" job (or any random citizen/soldier could do it, doesn't matter much) could build these near the territory or near enemy territory. Like the towers, they would take a bit of time to build, although they should probably be quicker.
The other option would be similar to boats. I mean, there's already a code for a building that can summon things. Why not just re-texture the boats so they can move on land and look like siege equipment and alter stats similar to how other cultures have different boat attacks?
I get that it's already been suggested but I'm curious to see if what you guys think?