How about mastery ward skins

I really doubt that riot will give us champ skins for masteries unless they want to give everyone a 520 skin (don't see that happening). So that makes me think, since every champ has a role, why not create and give us a ward based on that role when you master a champ. For example Ahri is a mage, if I master Ahri in this case I'd unlock the mage ward.

This does 2 things: gives everyone a way to get and show off mastery a of a champ and it encourages them to ward more (in theory).