It would be neat if there were traits that triggered after kills. Instead of giving them random chances to proc, they would instantly happen after a kill. I have a few ideas, feel free to post any you have.
Boost - Mobility is increased by 10-15 for 10-15 seconds.
Scavenge - Gain reserve ammo equal to the size of your gun's clip./Automatically pick up the ammunition of the person you killed.
Purge - All status effects are removed. (this includes DOTs, ice, muffling, and burning)
Regen - Heal 20-30% of damage received in the last 5-10 seconds from the person you killed.
Dank - The screen of the person you killed is flooded with MLG killcam effects. (for as long as the "you were killed by" message is on screen)
Adrenaline - Stability is increased by 10-20 for 10-15 seconds.
Defuse - Any remote mines, C4, or grenades placed or thrown by the person you killed are removed if they can still explode.