The reason I stay away from really harsh lighting and shadows is because while it may look very realistic, in my mind it stops making sense once the players are involved.

For example, if I make a map where the inside of a building is dark with just a sliver of light coming in through a barely opened door, it looks cool. But what happens when the players open the door? The room is still dark. What if they're carrying their own light source, as they're likely to do?

Not to say the images aren't nice (I always find it funny when I can point to the exact texture someone used in my own Textures folder), but I've found it a technique that seems like a waste on battlemaps.