Champion Mastery as a requirement for Ranked
Why not allow only level 5 champion(or level 4 if 5 is too unrealistic) masters to be played in ranked games? So you need at least 14 full-mastery champs to enter the queue and you can only select those champs in champ select.
If ranked is really "ranked" in the sense that it is a serious, competitive queue, then this should be one of the rules to enter.
That'll prevent people from of course first-timing in ranked and also just encourage better overall play since everyone will be good at their champ. It'll be harder to get into ranked queue, sure, but after the initial 2-3 weeks of slogging, the ranked queues will be filled with much better overall player skill and gameplay. Plus this will get rid of smurfs completely.
Also, what about another requirement that you need to earn the Team Builder icons for every single role before entering ranked? A more minor requirement, but just one to ensure that people have at the very least a basic understanding of each role.
but you only have
or if you see
but could only pick
? You get cheated out of a lot of Champions just because you haven't played to Mastery 5 with them.