The use of icon to add visual improvement to menus is becoming more common on the web and especially in cms's. I know this can be and has been done by contrib modules in various fashions. But it would be much easier if it was a standard part of drupal's menu systems. In particular, it would be better if a themer could implement iconic menus without doing any php coding but with with css alone. There are 2 techniques in common use:
(A) A combination of class definitions in the markup and css to define and style iconic menus.
(B) Use of the html data-* in the markup plus css to style the iconic menus.
Each method has their advantages and disadvantages. But both require some additional markup to achieve their purpose. The problem then is how the additional markup is achieved in drupal.
I propose method (B) here. By taking advantage of the existing admin menu management system, a 'data-*' attribute could be added to every menu item in drupal. A themer would have to add the appropriate css to use the attribute but would not have to write any php to use it. It offers a dynamic and flexible system for implementing iconic menus. It would also be easily 'localized'. A set of drupal 'standard' css files could be provided to establish a drupal standard 'look and feel'.