The sun is a great tool, but it needs two settings to up the game in rendering.
1 - light intensity multiplier
2 - shadow hardness
3 - shadow intensity
See how hard it is here. OpenGL actually looks smoother due to this:
I often want to set the sun accurately for the site and but when rendering the shadows are too hard on the edges to look right, and that causes hard contrasts that draws attention to the shadows instead of the objects in the scene.
(Landscape photography is better on slightly overcast days due to this)
I often want to indicate the shadow with out drowning elements in the darkness of it. So to be able to control the shadow intensity would be great. And if I try to light up the shadows with another light then everything can get over exposed since there is no exposure settings for the camera, nor for the sun. So please add that to the sun. (And to the camera )