Not sure what you mean here at all.
OKW has the most useful set of units of any faction, it is just that they don't have to use them because Volks and Obers are so cost effective. Seriously though, there are only a few OKW units I would not use at all and as such they inherently have more combined arms. You seem to suggest that combined arms only counts if you have static weapon teams with mobile infantry.
USF doesn't have combined arms because rifles is all they can do.
OKW has good stock units, but no actual support units. You have 1 indirect fire unit, that's it. No mortar, no non-doctrine MG, no AT gun, no medium tanks.
You see lots of Volks ---> Obers ---> Panthers because there are very few things in between worth building if your doing okay early game. It's encouraged to rush your Schwer because it gives you the only tools you have to fight Allied medium armor reliably, and with the fuel penalty getting light vehicles is highly discouraged.
OKW AA HT going over m20 mine is just a set back.
What the fuck. The OKW fuel penalty makes every loss harder on it, not easier. At the 66% fuel income the loss of a OKW AA HT is 71.5 fuel down the drain.