How about updating some other aircraft than US ones?
Updated and newbuild:
American:
B-17G
B-24J (new)
B-25s (new)
F4Us
Jeep (new)
M4 Sherman (new)
P-38s
P-39s (new, soon)
P-47s
P-51s
German:
Bf109s
Fw190s
Ostwind (soon)/Wirbelwind (new, soon)/Panzer IV H (soon?)
British:
Spitfires
Russian:
La-5FN/La-7 (soon)
T-34/76 (new)
Japanese:
Ki-84 (new)
Italian:
-
EDIT:
I'll add my top three choices for an update, based on how they look:
F6F-5
N1K2-J
C.202/C.205
And personally, I want to see the Mossie updated, but it doesn't look that bad compared to some others.