Concise description:
In addition to having an overall winning percentage, have a separate winning percentage for how many people are involved in the game. And possibly for different game types. Your winning percentage really is meaningless if one person only plays 2 person matches, while another person only plays matches against 8 people.
Specifics/Details:
ie..)
Overall Winning percentage :25%
2 players : 50% 9 games played
3 players : 30% 12 games played
4 players : 90% 1 game played
5 players : 0%
etc..
This of course can go much deeper, I am just suggesting a simple upgrade, but this can further more be broken down by spoils, maps , games including specific opponents etc. Would be nice to see how you do against people in your "friends" group. I play several private games against friends, it would be nice to have a breakdown of stats for those games.
How this will benefit the site and/or other comments:
It's interesting to see how you fare against other players comparing statistics.