That is a pretty cool idea, though it probably would never get added. I'd still like to see a wins leaderboard.
We should have both:
-Wins per day/week/all time leaderboard to promote active sparring and show the players with the most wins in the game's history, as they deserve it for all of their effort.
-Something like that division system, not counting towards wins or losses, for those to see the "higher skilled" players.
Because let's face it, nothing is going to get more people in the battle arena besides the long-overdue wins leaderboard.