mastery requirement for ranked games

this is something i thought would be an interesting idea. i can easily see some clear drawbacks to it and some clear advantages of it... and overall i haven't decided if i think its a good idea or not.. but here it is..

prevent people from playing in ranked with a champ they have less than a lvl 4 mastery with.

positives: this would help prevent people from playing champs in ranked they have no idea how to play.. even if there is an op champ if you you should learn how to play him before playing him in ranked.

new release champs in ranked games this is another issue that this would prevent.

negatives: would create even more non ranked people trying to get games with the new champ on release so they can play them ranked sooner.

would restrict champion pool for ranked even further

i was wondering what other people though of my idea or if they had any other positives or negative consequences this would add