Nice idea, its a good way to give personality to different teams and cities.
I think I would like it better if the diamond was the most prominant and the 'frames' were more backgroundy
. Im sure thats easy to do by changing the layer opacities.
I really like the retired numbers idea as well. It would actually give me a reason to pay attention to the #'s of players. Championships and retired numbers along with the background frames would really add a lot to fictional leagues.