+1 Add it. 
Just perk it like a 262. I love the ability to fly such a diverse set of planes. More is better.
IMHO, I don't like being inhibited from flying cool planes that actually existed. Who cares if only 25.7 were built, or was only used in 3 squadrons, or bla bla bla. It if existed during WWII and it actually flew - I'd like to fly it too please.
I'm totally with Slade on this. Give me Vultee P-66 and Vengeance, TBD Devastator, Curtiss Hawk, Seversky P-35, Do335, the 410, Bachem Natter, Blackburn Skua, the BP Defiant, F7F, Meteor, Faireys Battle, Barracuda, Fulmar, Albacore, and Swordfish, FW190-D11, the Me410, Do219, Do17, Bristol Blenheim, Beaufighter, Me323, He111, Ju188/388, Henschel ASMs, Re2000, Gr.55, De520, Ms406, P63, P59, Vought Vindicator, Curtiss SB2C, C46, AR240, Horten wings, Mistel, P-61, Raiden etc...
More is better. If there's flight test data, who gives a rat's rook if it flew at squad strength? Just restrict "irregulars" to a special Luft '46 arena or perk the hell out of 'em. Further, for any who might argue for a "just like real life" experience, I can only presume, then, that we're going to do only Axis v. Allies arenas and that the maps will be real-life ETO/PTO/MTO ONLY and that types and quantities of planes to be upped will be normed to some statisitcal representation of some period in the "real life" war. Where do you stop with such an argument?
That whole argument got mooted when somebody created AHII - for computer games and real life are not one and the same. Given my death count, I count that as an advantage to AHII.