Riot missed a golden opprotunity with this one and I hope they higher some physics majors to make better equations for them.
Nah. Anything other than what they did would have been a horrible idea.
Give people more points or only award mastery of a champ for stats based on KDA and total CS?
People already freak out over KSing. Riot should give them more reason to? There are already enough people out there that refuse to group and win games. No reason to award them for trying to pad their own stats by split pushing.
Only give mastery of champs for an individuals best champs?
I'm better at Leona than Thresh. Because Leona is easy as hell to play. I know that. Don't need master Riot equationists to inform me of what I already know. And maybe I play certain champs in certain sorts of games. I'd probably a Lee Sin Master on my smurf account from the insane KDA I had when playing with my IRL friends. That would be stupid. And so would Riot motivating you guys to friend request my IRL buddies so you could stomp bad players to easily become 'masters' of your favorite champs.
Give people champions mastery only if they perform at a certain skill level for a champ?
Well, I want that skill level to be Gold V. Pacov wants it at Plat V. Cow wants it to be Diamond V. Wherever you put the line at, Riot is putting a lot of effort into making a large portion of their consumer base feel bad because they can't be 'masters' of any champions.
So yeah, Riot missed a golden opportunity to raise the toxicity levels in games and alienate casual players. Instead they introduced a fun little thing for us to show off what champs we like to play most.