That was the hardest part for me. I made this just for fun but I thought it would be a nice gateway into a new timeline of air warfare. Especially in this amazing Game Engine.
I would love to see the sub variants of the F4U as well. I chose the F4U-4 because I think it was used the most of the US Naval Props. The AU-1 is even better with a much, much heavier ordinance load and more choices or ordinance. The F4U-5N, NL were night fighters. I do not see any serves thus far supporting night operations. So, I think wasting dev time on that bird is frivolous.
The F-51 and F-86 can cover many Air Forces as stated above. In order to make this, I think they'd have to go to a 'RoF' type store and just release a couple birds at a time. B-29 would have to be AI. That plane just has way to many systems and details that would be dev project just as big as the game itself.