Yoga is a very effective way to develop body awareness.
Some of the best and most coachable athletes I have worked with have had a tremendous amount of body awareness. Because of this fact they develop technical proficiency and make technical changes with greater ease.
A yoga practice develops body awareness through having swimmers perform movement patterns that they are unaccustomed to which develops greater variability within the nervous system. Greater body awareness is also developed through the encouragement of bringing specific attention to how the body feels at different points in the practice.