Currently the way you rank up is by winning competitive matches, but winning alone allows people to boost their accounts or smurf games to ruin other people's experiences. I believe it would be more effective to rank players by their match score. Your match score (from what i am aware), is the total combat score you earn in a match. And after a certain amount of competitive matches it should take the sum of all the match scores and rank you based on the sum in specified range list. For example, out of 15 games, you score 5,000 points every game, you get placed Gold II for hitting 75,000 points and so on.
Note Im just bringing up the idea, not fully thinking it out.