As you know there is an option to switch from user picked colours to team colours where all your units get blue icons, allied units green icons, and enemy units red icons.
It would be useful though if there were an in between setting, where both the unit colour and icons of yourself and allies got discrete colours in the blue-green spectrum, and enemy units and icons got discrete colours in the yellow-red spectrum.
This would allow players to both quickly identify friend from foe, whilst also determine the unit's ownership (and thus faction and rating) at a more thorough glance.