It would be nice to have some indicator when we kill some enemy. It's really simple but I like to realize when I get a kill with some sound or a visual marker that I've killed an enemy, like for example Bf1 does, a red marker in the center of the screen with a characteristic sound.
It would be also really useful when calling in artillery strikes, so you may realise how many kills you've got. I even sometimes don't realise that I killed lots of enemies and when I see my current stats I see I got like more than 10 kills and I didn't even know.