your are definitly going the right way with the terrain,as the most important buildings are usually on highest part of town be it castle or church.e.t.c I think bringing in some hills, levels will make this a killer city.Looks great.
An old bridge and river would be cool.As for the platform below the church
i would put some coloured large umberellas to show a outdoor boozing area,
so you could sit down ,drink ,look over the city and listen to a jazz band..