I think the lesson here is that realistically modeling all these aircraft is a tough job. We've got primary documents that contradict each other. WW2 pilots that contradict primary documents and themselves. We've got groundcrews and pilots making modifications, often sparsely documented, to their aircraft during the war to change their performance compared to others of the same model. We've got aircraft that no longer even exist any more. While we have people with real life flights in actual WW2 aircraft, this is only available for a few of the aircraft in Aces High, the rest have to be modeled on best guesses and their true performance will likely never be known with any certainty. And that's before even considering the modeling of guns and ammunition.
It seems likely to me that the P51 is one of the best modeled aircraft in the entire game. Many survived the war to this day compared to other fighters. The 50 cal is also likely one of the best modeled armaments in the game, with tons of guncam footage and lets not forget that the 50cal is still widely used as a weapon today, not much changed from WW2.
So it seems to me, if you're going to complain about aircraft modeling, you'd have a better argument to say that everything else is overmodeled compared to the P51. The P51 is probably the most right fighter aircraft in the game, just based on how much easier it would be to model it right compared to everything else.