Mastering a Champion means Champion face summoner icon

I was just playing League when I was like, "Know what we should have? Summoner Icons for Champions we mastered." I mean Mastering a champion is cool in of itself but whats the real benefit? Sure you play a champion a lot so you master it quickly, BUT summoner icons will be for everyone to see, not just the person you are playing as to have a boarder. A summoner icon could allow you to play another champion but still give respect to your best mastery champion/ whatevery champion you want to display that you mastered.