You should remember, that you sometimes can't win, because your team sucks.
Win/loose ratio is good to see next to K/D, it shows then how much you help to win.
Next good stat could be Average points per round or map
well no, because of the nature of statistics, if your average win/loss is 1.1, that means that
you are contributing to winning the rounds that extra 0.1 times above the average player, not that you're just getting lots of peasant kills as would be the case with k/d
it'd be kinda cool if the autobalance system was taken into account with the k/d thing, so the way people are autobalanced (i think) it gives players a number based on their k.d etc, be kinda cool if you got more points for killing a 'valuable' player and less for a level 3 peasant
just a thought ^^