I follow this game a lot and now i heard about water - sea/rivers actually working, also fishing already in progress and much other things.
I see building as really really important part of this game and i would like to see it evolve.
So my suggestion and idea is, not sure if someone already posted this, building houses on water. I was lucky person to go around world and see lot of places that use this kind of building. Most of this houses are pretty old looking and i think they would fit great in this game. Houses would be made from wood, leafs and they would sit on platform made of hard wood that is supported with pillars. So its not boat house, its not moveable.
Here is picture of example
Sorry for my english