I would really like this. But I've yet to see a well-done ranking system that really keeps similarly skilled players together. Are you aware of any such games? A lot of players aren't interested in competing in their own skill range. "newbie" servers are regularly populated by pros who enjoy being top-of-the-leaderboard. (Hey, who doesn't?)
In a lot of ways, I think persistent stats such as Battlelog (as cool as it is) defeats a lot of the fun. I really enjoyed CoD 1 where your stats extended as far as the round at hand and were reset for the next one. No one knew how good anyone else was, they just PLAYED the game. CoD 1 is the most fun I can ever recall having with an MP FPS.
With systems such as Battlelog, the actual gameplay is subservient to the RPG-esque stat system which must be carefully maintained, and even padded in most cases. It would be interesting to see how many people would just turn their stats off completely if such an option were given. I know I would.
SC2 ranking isn't too bad, but none of them are perfect. Yet.