I didn't know where to put this exactly, so I figured I'd make a topic on it on the 1.8 sub forum. I opened a city I've been working on that I used MCEdit to build, and even when the render distance was far, there was a grey fog and I'm hoping this is just a bug in the game. I took a picture of my map on 1.8 and another on 1.7.3. The top picture is 1.8
and the bottom is 1.7.3
The top picture is 1.8
and the bottom is 1.7.3
The map you are playing on has the playing area very close to the void.
Or revert to 1.7.3, or maybe find a height mod.
The minecraft world wasn't meant to be to be like that.