As a mainly solo player that sometimes picks up random people or join others in their vehicle, I have been wanting this since forever. The time I was in a outfit it would also have been really nice since it could get really messy with coms and different pairs of people in a squad driving around in vehicles trying to communicate with each other in the squad and at times only 'their' vehicle. "Tank to the right!" Everyone looking right, even though they may or may not even be in the same area and so on.
I think that besides a tank-only chat we need a quick and easy way to place short-duration visual markers on the battlefield. That way you dont have to worry about the individual orientation and knowledge of each person you are communicating with but they can use their own knowledge and orientation to make judgement calls, even if you werent aware those allies were nearby. For example, hold the V button and you get the radial menu we already have when holding Q on an ally, only your options are to place a marker on the ground with a specific meaning. Like "AA here" to warn nearby aircraft or "enemy armor" so allies can react to them even if they dont necessarily have LOS or their minimap enlarged enough. This is especially true if the markers are visible like a waypoint, and guide the player to it even if they are looking the other way. Similarly the Q button when held on a spotted enemy could also give you a radial menu to ask for quick things like an airstrike (especially handy at guiding nearby aircraft to a tank that keeps popping behind cover for repairs) or requesting infantry support against a target. The best part is that such a system can be used to let players communicate with anyone, even outside their outfit/squad/platoon. You are rarely in the same group as the air support currently flying about and often squads or platoons tend to go for single units, making it hard for infantry and tanks to easily communicate and support one another. This system erases that, since it doesnt matter how many people you are communicating with, where they are, what their orientation is or what they are doing. Add a bit of contextual preferences so a tank will see tank-related markers from farther and for longer than infantry/air related markers and you can prevent clutter and get the most out of it.
