I disagree with the mentality of "it was made, it fits into a sim" because you're taking the feel of WW2 away from the game. All of a sudden it's Luft '46 in IL2 all over again.
Yes and no, if we're dealing with a historical re-enactment certainly. However if we're dealing with a combat flight sim whose plane set is defined as planes that were production variants (as opposed to prototypes etc) then we have an entirely different animal. Currently we seem to have a "saw combat" criteria which I think is a bit unfortunate since it removes planes that were very much available like the Meteor or who's production was derailed do to natural disaster (Grace) or act of war (Do-335) or politics (F-7F). What exactly is the "feel of WW2". Is it a spit IX in the early war arena or P-51 in the mid war or a 262 in the late war? WW2 wasn't "a game" it was a bloodbath. This however is a game and it allows whatever leeway the designer wants.
No question that combat theater will address the "feel" of the actual war and provide a more immersive environment for those who want it. IMO the MA is just a place to play with the toys that were available at the time. Personally I'd love the Grace, just like my A-20 I'd be out hunting scalps not carrying the mail with it. But I'd love to see the Do-335, meteor and F7F as well. In fact if we look just at the D0-335 we have one of the most intriguing stories of the war.
The plane was actually available in 1942 (Suprisingly its a 1939 design that Goring canceled development of in 1940). It then was awarded a production contract in mid 1942 which was then canceled before a later protype was ordered. It 1st flew in 10/43 and was ordered into rush production in May 1944.
So here we have a fighter that might very well have entirely blunted the US daylight bombing campaign that was delayed and altered while inferior planes like the 109 & 190 continued to be upgraded and produced. Had the D0-335 been produced in early 1943 in large numbers the entire course of the air war might have altered...so yes I'd love to see it as the single biggest "what might have been" question of the WW2 air war.