Allow fireteam leaders to command their team members while still being able to receive orders from the squad leader. Squad leaders should be able to easily distribute orders to fireteams without going through the clunky process of the "coloured teams". This would encourage players to use military units the way they were meant to function.
In ArmA 2 this could be done with the high command interface, but this only worked with human players.
Bind the available command interface to the rank of the unit. Corporal = current per-soldier interface, sergeant = per-fireteam interface, per-soldier interface for own fireteam, lieutenant,captain = per-squad interface, per-soldier interface for own team, etc.