I think the only way something like this could really work out is if it were strictly limited to match environments. Otherwise people will jump on a speed server, spawn camp for a few minutes and get 500 kills to improve their rank, or constantly switch over to the winning team, and use other cheap tactics to get points. Match only stats would:
a) Promote matching and clan activity.
b) Reduce stress on the stats/login server, since matches aren't as frequent as pub play.
c) Allow for more team-oriented scoring (ie: award points for matches won, rounds won, flag captures, etc.)
d) Make the stats have more meaning, rather than just how many "pub newbies you can pwn"
e) Allow for much more detailed statistics.
One thing I'd like to do is have the points scaled by the rank of your opponent. For example, if you kill somebody with about the same number of points that you have, you'd get, say, 1 point. If you kill some newbie who has almost no points, you'd get next to nothing. If you kill somebody who has like twice as many points as you, maybe you get 2 points. This would encourage people to match against higher-ranked players so they can rank up faster rather than repeatedly preying on newer clans to pad their stats. It would also allow the skilled players to quickly climb up in their ranking and it would be more about who is has skill rather than who has the most free time to rake up points.