A kill counter would just be another "false" stat that people would fawn over and wouldn't accurately measure the work put in by that player. What I mean by that is it won't capture the essence of what it's meant to measure. For example, look at the leader boards. Most new players look to as a gauge of who the most skilled individuals are, and are proud of breaking into the Top 10. However, all it really measures is who has played the most during the week. There are plenty of players who aren't on there that would wipe the floor with those who are. As for the damage stat, it tends to measure who was the most aggressive more than anything, and isn't an entirely accurate measure of "skill." Player A can fight 10 people all match and win all of them single-handedly, but his damage can be dwarfed by Player B who just ran with the team and GF-swung into a crowd of distracted enemies all match.

To me, your concept of a kill counter was conceived to try and measure one's killing proficiency, please correct me if I'm wrong (it's late and my mind is all fuzzy). The problem is that most people are too short-sighted to see the variables involved in how people's stats came to be for the round. If someone gets 20+ kills at the end of the match, other players can incorrectly assume that all those kills were earned based solely on that person's efforts, when the reality is that it more than likely wasn't. False praise and regard for that person's ability would then ensue. As it is, in fights when one person nearly kills another but is instead killed by them, and a second player comes in and finishes the victor off in one blow, the newly-killed player tends to attribute the circumstances of their death solely to the newcomer.

I'll use the above three forum names in the following example: Sigle and Klipik are dueling; Sigle brings Klipik down to 10% health before being taken down himself. Doctorspacebar enters and finishes off the weakened Klipik, who then goes on to praise (or curse) him for the death, all while ignoring the fact that it was Sigle who did 90% of the damage. Would the fact that all Doctorspacebar had to do was connect once to "earn" a kill be reflected in the kill count stat? No.

Damage stats aren't perfect, but they are better than kill counts. Time spent capping and uncapping would be good, but I'm unsure of how difficult that would be to implement. An assist counter would be interesting, but there's the potential for "abuse" with that.