Level 5 Mastery Rewards

I was just thinking of an idea for the mastery system of late which involves at the time of achieving level 5 mastery with a champion, unlocking the champion icon as a Summoner Icon for the certain champion and/or unlocking a special unique ward skin specifically made for the champion at level 5 mastery. I think it'd be a really cool idea seeing as I love to play a certain few champs a lot such as Yasuo and Lucian so it'd be a total reward to earn a keepsake for my level 5 masteries other than the level 5 emote.