As someone whose child plays multiple positions, I can only extol the benefits of versatility. The reality is, kids must learn to play with AND without the ball, on BOTH offense and defense.
Also, as someone who has (extensively) coached another sport, I can tell you that beauty is in the ye of the beholder. Different coaches see different things in the same kid.
Encourage your child to learn, practice and master the total game, and watch his/her playing time increase.