If the US counters are to be olive green, then making their map colour olive green as well seems like a really silly thing to do. You'd spend ages looking for the counters.
As for the layout of the counter, let me ask a question: what is most important, the nationality of the unit or the troop type? To me, it's the nationality, which is why I made the flag the central, largest element. As a player you want to see
your units (and those of the enemy) clearly. To find out what type of units they are, you'd be clicking on the stack anyway (because the screen only shows the topmost unit), and then you can see the unit types on the right-hand side. Therefore, the unit type markers are pretty secondary.
In fact, I could argue that the counters should
only show the following information: land, sea or air unit, and perhaps infantry, cavalry or vehicles (though even that's debatable). To get anything more precise, you would need to engage the unit in combat - there are no spy satellites in 1914, and reconnaissance units would only be able to say "large body of troops", not "militia" or "attack division".
Land. sea or air could even be shown by a white or grey broad stripe along the counter (bottom edge for sea, top for air, none for land) rather than a symbol.