What riot should do to rank game system

I think riot should set a champion masties requirements in rank games. like at least level 3 masties and only the champion that has level 3 masties or higher are able to pick in rank games because they are so many people in their rank use champion they never use before. And they feed so hard. Oh in some cases he just go 20/3 on a champion they never use in normal once. That is boosting. Is not fair for the community and not fair for the player itself cuz he never learn how to play the game