I foresee a problem now that we have "Premium" Memberships (which are a very good thing, BTW). Since "Premium" members do not have game limits, they will be able to play many, many more games than non-Premiums. As a result, they will be able to move up in rank much faster.
Some people do not want to become Premium (either they can't afford it, or enjoy CC just this side of obssessive), but will be essentially punished on the Scoreboard.
I suggest that in addition to points and rank we create points per game (PPG). This would be a true rank of players ability since it would account for the number of games they play, the caliber of their competition and the number of players in their games. Except for hockey, all major sports use a variation of this (NBA = PPG, MLB = AVG., NFL = Completion %)
To eliminate statistica anomalies, we should probably have a minimum of 20 games to qualify.