Its really interesting how u fade to grey in the middle of the cobblestone.
Its good how its only a few extra colours to get that effect and the gradient isn't even visible on my crappy monitors.
It looks like the colours were changed using tool assistance though which is fine except you've ended up changing all the highlights and shadows on the cobblestone.
This is a waste of colours and also doesn't make much logical sense as it seems like the top surface would normally be the only one to be come worn.
Its barely noticeable but I would change all the cobblestone highlights and shadows to the same colour to keep your count down.
IMO consider keeping cobblestone horizontal as it is a horizontal plane.
This isn't required but seems like normally the way to go where you have a choice which directions the lines would go.
Typcially choosing vertical lines for vertical walls and horizontal for flat ground.
Not sure how to explain it except that its a visual communication thing as if its easier for the viewer to process and accept it with less thinking.
R u going to have any vegetation?
Re your comments about making a cute and fun environment, I thought this was the case but you can still keep that vibe and add texture if you want.
You just need to keep textures subtle enough they don't conflict with surroundings.
Here's some barnacle references in case you like the idea...
http://thumbs.dreamstime.com/z/barnacles-weathered-pier-piling-21990568.jpghttp://en.clipdealer.com/preview/image/003/151/072/previews/1--3151072-Barnacle%20Covered%20Pier.jpg