It is important to be clear that the Sun Object is a lamp and the LightWorks Sun is the horrid built-in sun.
In either case, darkness of shadow can be mitigated by:
1: best: adding a sky object - shadows, yes.
1A: adding a manually-adjusted sun object that fills the shadow and casts no shadow.
2: worse, but can help the sky object, too: increase general ambient light - pick ambient color in the camera dialog.
3: float a general light sllightly off camera and above camera viewpoint - this isn't great, but at least you can control the color of the general light - yellow - unlike the ugly "do-I-really-look-like-that-when-I-have-been-drinking-AND-singing-AND-dancing?" camera flash.
Be sure to turn off the sun and turn on lamps and ambient in the rendering dialog.
Dwight Atkinson