If you properly use fill flash, the background will be better with the subject and eliminate all shadows. Fill flash can also get rid of dark circles and imperfections on a person. If you want less intensity then you can adjust the flash. Its important to put the subject in an angles position with the sun. When using fill light you can use a reflector to help your subjects face glow. You can take up close photos with flash too. You can adjust the color temp of photos to get it more live looking while also making things look as natural as possible. You can be far and close for flash fill photos but the lighting and where the sun is pointing as well as the shadows is what is most important or else things could be underexposed/overexposed.