Isn't it quite normal to keep track of your kills? For example: ww2 fighter pilots, tank crews, snipers etc. I bet they all had a somewhat accurate estimation of how they did.
The way I would like to see the scoreboard working:
Ingame the scoreboard is not accessible but when the mission ends you could see how you did and who you killed and/or who killed you.
I think the scoreboard is closely tied to the "kill-messages" which occur when you kill a human player. I'd like to have an option to turn them off completely.
example with "kill messages" ON
You see a group of soldiers walking towards you. You open fire and kill the first one. A message appears that you just shot a friendly guy and you know to stop shooting.
example with "kill messages" OFF
You see a group of soldiers walking towards you. You open fire and kill them all. When the game ends you learn that they were all friendlies. Triple the fun on irc.