Could do like in games like league of legends to add an assist counter in the tab view. However I dont think it would be too informative. Who cares that you might have accidentally hit 5 people?
If you did one damage to every enemy with 1 accidental pellet your assist count would be insane. But in reality, you did very little to help your team win. Damage counter is whats currently being used to determine "usefulness" or how good you are, and its much better at it.