There should be a heraldic armor for archers/light inf. that is leather, but with a heraldic badge sewn to it on the left breast, or even something on the full chest that reflects the main colors of the banner. Not sure if this can be done, but it would be awesome to see in strategus battles, and would be historically accurate.
Most armies couldn't afford a cohesive "uniform", so to tell each other apart you used heraldic badges and banners. Adding banners ain't a bad idea either to think of it.