Lol you cant be serious...
Lets pretend for a second that it was the one and only thing that mattered when comparing accounts...
1) What if the person was facing more noobs then good players? Might that affect a K/D?
2) What if the person was playing against a lot of cheaters, hackers, or boosters? Might that affect it?
3) What if the person was one of the cheaters, hackers, or boosters? Might that affect it?
4) What if the person was constantly double/triple teamed? Might that affect it?
5) What if the person had someone else using his account? Might that affect it?
6) What if the person didn't always play to his 100% skill ability? Might that affect it?
The list could go on and on, but you should get the point by now...if not then idk what to tell you.
If you want a list not concerning comparing accounts, and just based on skill, I could do that for you too, lemme know :)
[Edited on 12.18.2010 8:41 PM PST]