This recipe could be improved by dredging the chicken in flour first, then putting it through an egg wash, and again through more flour. This is a great way of making sure the flour sticks to the chicken. When the chicken recieves only one dredging of flour, the coating may come off in the pan, especially if you do not use a non-stick pan. Furthermore, a non-stick pan will deprive you of the fond or browned bits which are the foundation of this sauce. Some people put the chicken through the egg wash first, but since eggs are slimy and so is the raw chicken, the egg doesn't adhere to the chicken. By dredging in flour, egg, flour one creates the best possible coating.
Slicing the garlic instead of mincing it will give it a more mellow flavor and will allow the flavor of the Marsala to predominate.
Reducing the sauce for 4 minutes at the end and enriching it with 1 tablespoon of butter or 1/4 cup of heavy cream will also make the sauce more unctuous.