I dislike people bemoaning the art style of the screen shots and gameplay footage that have been thus far released for Diablo3. We have only been shown with a small number of environments. They are presumably from the early game levels, since that's likely the most polished and there fore most worthy of presentation. It's very possible that there is a progression towards darker, more edgy environments later in the game.
The president is there from its predecessors. The tile sets in the original Diablo became progressively darker, the deeper under the cathedral you went. Even the varied environments in Diablo2 showed a movement, the further you got in the game, toward a darker, more suffocating atmosphere.
I think people will find most anything to complain about, and there's really not enough details available yet to come to any sort of reasonable, informed option. We'll all just have to wait for more bread crumbs.