Champion Mastery

So I just finished playing a ranked match with a Cassiopeia who had only played that Champion 5 times ever in all game modes. Since you're implementing this into the game, you should also implement something that prevents people from playing champs that they haven't played at least xx amount of games with before entering ranked mode with it. Naturally this person had never gone positive once in the 5 games they had played as Cassiopeia, and I wasn't toxic after the game. I just explained why it fucked everybody over playing a Champion you're not the fluent or good with in a ranked match. I feel like it should be common sense, but I am mistaken each and every day. Using something like this would prevent new champ feeders also.