Don't worry, someone is bloody likely to make some Equestria Invasion something mod since they've already invaded V2 and CK2(?).
I think
"My Little World War: Friendships of Iron" sounds better.
Back on topic, I think an extra unit pack would be nice if it just added things that were too rare to warrant inclusion in the base game but did actually exist, like Super-Heavy Railway Guns or purpose-built Kamikaze squadrons. I think this would help make the game feel more deep and contribute to the WW2 feel.
Fantasy weapons are a low priority and should be left to mods.