Although I know that you think that the shadows are too dark, I think that might be appropriate for some settings. The world of the gulleys is a dark and forboding area.

However, currently the shadows of the bluff fall evenly regardless of the elevation of the terrain the shadows fall upon.

The bridges, for the most part, should be above the shadows and in the light. Likewise, the bluffs should rise out of the shadows. I recommend masking those areas and erasing or increasing the transparency of the shadows.

The change in lighting should really make those areas pop out at you.