I would like to see :
Bone, straw, little branches and pelt homes and tents , to have eventually moving camps or very low tier ones … totally destructable by iron weapons and up.
Make the tiers from 1 up undestructable by weapons apart doors, All doors should be diestructable with pickaxes, axes, swords and all those king of weapons with varying degree of success… only doors.
Also reinforced doors , done with improving the doors exhistant should be immune to those weapons …
Tier 1 :
Tinder and wood buildings for North with insulation capabilities
Mud and straw buildings for Swamp and Jungle areas.
Because the building do not match the surrounding style of the environments and create an unpleasant view.
Jungle stone carved buildings for Jungle areas
Reinforced Stone carved buildings for Jungle areas
Also make rocks picked in the different zones alter the colors of the construction so that if I build an arenaria wall in North I have t ouse the local stones and will look gray and not red … do not allow mixing of stone types so no red and gray wall next to a red one and so on , but you could eventually allow mixed stones so create a wall made of alternate colored pieces … but that too much I guess and not really needed , just make incompatible the two walls next to each other eventually to preserve a visual style.
Reinforcing Tiers With Upgrades…
In order to preserve the visual style of the tiers, if someone wants to keep the look of a tier one or two , allow to improve the walls with reinforcements to be able to upgrade to a resistance of tier 2 the tier 1 without changing the visual appearence … and so on with the other walls …