A change in the Mastery system is needed.
I don't understand why you need to level up to get keystones. It just doesn't make sense. Masteries make a huge difference in matchups, for instance, two players with the exact same skill level and champion, would be a stalemate. But when one player has a mastery, the other player is at a great disadvantage. I don't understand why level 17 is needed for keystones to be available, it just puts lower levels at a disadvantage.