Either it's a World War II game or it is not. Players like Colt, with ideas about customised shoulder patches, should be looking at another game. No offence intended.
There ARE realistic examples of customization that can be done (and were done by soldiers on the field) in regards to the uniforms.
Granted, aside from some standard things like painted/non-painted helmets and few other bits and pieces the customization soldiers did on the field while existing weren't as common that every single soldier had a completely unique look to them which would be rather apparent if such system was present here. Though for gameplay and fun sake, I think it's a sacrafice worth making.
Firstly I think adequate uniform models for soldiers as they rank up (I think some ranking up and progression was in plans if I remember correctly) can affect uniforms in a realistic ways, like German soldiers starting out with a cap and then unlocking a helmet as they upgrade, visibly different rank insignia and medal awards on the soldier and other small things would be small but important details that greatly help break the monotony and immerse players. Even letting players choose between normal or rolled up sleeves would visually make a significant difference between every soldier looking the same as the other and feeling you're in an actual war.
Having a few face presets, even if players don't get to pick them, wold break the immersion-breaking feeling of "hey, I just killed 4 identical looking people in same room". There don't have to be a lot of them, even having as little as 3 different faces helps greatly.
Combine 3 different faces with 3 slight variations in skin tone (I'm not saying drastic variation akin to Asian, black and white, but perhaps just 3 versions of Caucasian skin tone that are just big enough to notice).