I don't agree that the aircraft left to be modeled would only be useful for scenarios.
German:
Do 217 (anti-ship missiles?) One of the few.
He 177 Absolute disaster as a warplane, had no effect on the war. Falls under my description.
109G-10 Inferior to the Bf109K-4 and introduced after the Bf109K-4.
190A-6 (like an A-5 but with better armament) Saying it is like the Fw190A-5 isn't really putting it out of my criteria. How many A-5s you see in the MA?
Ju 87G (Heck yeah I would use this to bust tanks) Would see low usage compared to the Il-2. The 6 round clips would stop people.
British:
Spitfire XII ~100 built, falls under my description
Mosquito XVI Another one of the few, you are up to two.
Russian:
Pe-2 Here is a third
Yak-3 Inferior performance to the Yak-9U, small clip would make it a specialty fighter.
Tu-2 This would work.
Pe-8 (4 engine bomber with 20mm defensive armament) Very few built, falls under my description.
Japanese:
Ki-100 Think of this as a Ki-61,except slower....
J2M5 American test pilots liked it a lot, Japanese pilots not so much. Maybe viable, maybe not.
Italian
P.108 I cannot begin to comprehend how you think this thing doesn't fall under the description I gave.