Some UNIT suggestions for next update...or the one after...some were done before...
Add some usable capability to unused units...for instance:
Ju88 is in game, not used by anyone...historically had good anti-ship capabilities
Hellcat was probably the fighter with more kills in the pacific...card is useless in game
Check consistency of weapons...some make damage to the wrong type of units...for instance (based on history but ALSO on the game OWN DESCRIPTION):
2 Pounder AA Gun has no bonus vs aircraft (its an AA gun!!!!)
Hedgehog is an Antisubmarine weapon...same issue...
Submarine Hunter affects ships? (not used in game...perhaps we need cheaper version...see Gus request above...of course i would prefer a Noborito improvement...but i am suspect

)
Some VERY USED historical units not in game:
Panzer IV
Panzer III
P47 Thunderbolt
B24 (both bomber and submarine hunter)
Hurricane
Typhoon
He111 (both bomber and torpedo plane)
A possible introduction of Ju87G and/or Hans Rudel...which are a famous "duo" that killed MANY Russian tanks...
Jeep ("just" half a million made...not a sexy weapon, but i guess you can give "unique" capabilities)
Lots of Naval Bombers...which could have antiship/antisub cababilites...Catalina, Sunderland, Avenger, Dauntless, Helldiver, Kate, Val, Judy...etc...
Lots of specialized antisubmarine planes and ships...
For some reason you decided to add some obscure recon (Seagull, Walrus, Be4) planes on last update...without any useful capabilities...not complaining really...just suggesting a different approach...not sure what sources you are using

10.000 Lemmings can't be wrong...