No no no, PLEASE, not K:D stats or anything like that.
It's simple, as lf said. People will play more for their ratios and skillz, like in CS. It is already a noticeable problem at times; let's not make it even more rampant.
I don't play for score, but I still notice it. If score becomes the main reason for playing, it would ruin the server.
Thumbs down.