It's easy to tell the nationality of troops in WW2 . Even back in the '80s infantrymen looked different to eachother. Nowadays it's really hard to tell who is who. Some countries may have a distictive camo pattern such as the Swedes but by & large I'm finding it really hard to tell who is who. (Coloured tape on the arm & helmet helps.)
Sort of thought the same myself, all the current helmets seem to have such a similar outline in particular. I find myself trying to work out what rifle they are carrying, then remind myself I'm at least 20 years out of date on modern equipment.