I'm sure that someone has thought of this before but i thought i would post my idea anyhow.
One thing that really annoys me when i'm playing is trying to find someone given coordinates. i think it should be possible to type a command like /waypoint and then the coordinates you want to go to and it would make a white X on the map like a mission and a yellow indicator on your compass.
another way to do it would to be to make waypoints like item references, so you could send them over chat to other people, and they could double click them to load them into thier map.
this would totally eliiminate confusion over "where the team is"
the would just send you the coords, you make a waypoint and follow the yellow line :P
I'm sure this would be rather easy to impliment since the same sort of thing is already implemented for finding missions.
*Another idea would to also add a line on the map showing you where to go, that connects your current possition and the destination position on the map with a blue line or somthing, would be helpful for finding out exactly how far away missions are. just like sometimes you run in the direction of the yellow line for ages until you get killed by somthing dark red because you had no clue how far away the mission was when you started.