Kev:
The 'dominance' is referred to as a dominance as a CV-based fighter. In short, our Aces High representation of a "naval fighter", is the most insignificant one of them all.
Sure the Seafire did see service, and were often in important theater of operations, despite small in numbers. But really, when we think of 'naval' planes, is the importance of the Seafire greater than that of the Hellcat? The Zero? The Corsair?
Furball:
Go away!

Mav:
It is a difficult thing to define the historicity of a game. You are right, in that Aces High is not a simulation in the respect that the MA rules of game playing is nothing like the war.
However, AH does have roles assigned to planes that is roughly simular to the real war, and the planes we see in the air are more often than not expected to fly and fight like real combat planes of the war. In that sense, when naval battles occur, no matter how gamey and dweebey, PT-launching, 5" toting, suicidal barging it is, people still expect to see real naval planes upping from carriers.
Not, Spitfires.
...
Besides, the stats Kev posted doesn't really help.
The Seafire is the same thing as the SpitV. Basically, it shows that the SpitV usage is at 29101 - roughly 5000 more in usage than the even the La-7.
SpitVs are one of the most preferred land-based planes, and one of the most preferred CV-planes, too.