A form of shortened name displayed on viewing the minimap to enhance communication between players who are at different locations, which could be toggled on and off via hotkey.

The ability to signal the map a-la Age of Empires 2, to assist with callouts.

I know it's been mentioned elsewhere as well, but a red reticule with a lit dot for headshots would be good too.

red part no you see who your are shooting -_-everything else i think i have to agree to