Blank textures, ultra shaders and close fog?
Though it's an extreme lack of detail, it is really cool. This kinda stuff looks great in like a town hall as a model of the city
Edit: what you COULD do to spice it up would be a variance in terrain around the area. Include a statue out in the water on an island, make some cliffs, consider a river or two, MAYBE trees? Maybe not. You'd have to see how they look.