This is all it takes. There are no naturals or prodigies in AHII.
The single most important skill, gunnery, is probably at least 50% natural talent.
This is compared to BFM/ACM which is mostly experience. Your flying is actually a good example Steve. When riding along with you, it quickly becomes apparent that the largest factor differentiating the sort of numbers you put up in a P-51 vs. what I or other somewhat experienced average joes can do in it is the fact that you simply don't seem to miss.
I'd say great shooting makes a great pilot more than any other factor, since it allows you to end a fight from so many more positions than a poor shot can. For example, overshoots are actually pretty easy to come by in the MA, but if you can't quickly line up a killing shot on a maneuvering target out to at least D400, then overshoot fighting is mostly just an exercise in being someone else's target practice. Making them miss, in and of itself, is just delaying the inevitable, killing quickly is the key. Batfink's ability to fly out of someone's guns envelope is astounding, but what makes him truly a threat in that Mossie is that one simply is not safe anywhere ahead of his wingline within D800. Same goes for energy fighting vs. superior turners, if you can't hit snapshots at all sorts of high deflection angles on a jinking opponent, then trying to E-fight someone will amount to demonstrating some aerobatics and burning ammo. If you are a poor shot, then you have to build your game around saddling up on the dead six at close range and plugging away, which is not possible with all plane matchups and takes too much time in a multi-bandit situation.
Since most of us are playing with on smallish joysticks with a couple of inches or so of travel to control the entire range of control surface input, fine motor skills end up being important. I think that if we all had floor-mounted full-size sticks with a realistic amount of travel, 90% of the complaints about nose bounce and the quest to find the "magic scaling" to solve these problems would disappear overnight.
I'd say overall the game is about 1/3rd ACM knowledge, 1/3rd gunnery, and 1/3rd equipment. (You don't have to have the latest and greatest equipment, but a decent frame rate, a monitor big enough for you to see easily, and a decent joystick that holds a stable calibration are needed. rudder pedals>twisty stick, etc.)