Idea for champion level 7 S rank reward

Was casually playing ranked on a champion i had just gotten level 7 and achieved S rank. It was then that i felt something was missing, wouldn't it be a great idea to continue to reward S ranks beyond level 7? and that's when I had an awesome idea. Why not give Key Fragments to player who achieve S rank on a champion that they have unlocked level 7 on? There are plenty of players with large amounts of chests accumulating and not enough key fragments to open them, as far as I have noticed anyways. This would encourage players to play champs that they already have lots of experience on especially in ranked.