Currently the cosmetic credits are shared universally, but I think it could be neat idea if you had separate credit amounts for both security and insurgents. That way you could customise them equally instead of having to split between the two. For example, the initial 1000 credits you get could be used to get some decent customisation for both, instead of like one camo and one keffiyah. And you could earn one item for each when levelling up.
Also I really hope you re-add the black and dark-grey clothing. I really don't think it affected gameplay that much. If they did, you'd need to remove desert camos too as they blend in with sand, similar to how black might have blended in with darkness (but I doubt it).