Noone has particularly promoted that the ammo counter was 'evil'. It's importance lies in the fact that it is merely another factor which persists, that might effect gunnery. The virtual pilots of AH still can count exactly the rounds left, and assign a certain level of controlled risk by "wasting it" at whim.
For instance, if I am in a P-47 with some 3400 rounds of ammo, I'd try a little spray up to even 600 yards, perhaps about 1000 rounds of .50s can be "afforded to be wasted", and it'd be an acceptable risk since I can stop exactly at 2400 rounds when I wish.
Clearly, without any specific ammo counters one cannot take the luxury of affording some rounds to be wasted.
More rounds in the air does increase the chance of hit upto a certain point - and it basically comes down to how willing the pilot is, to waste his ammo.
If he feels the risk is not worth it, he wouldn't bother taking pot shots at an enemy at 600 yards. Maybe fire a couple of streams and forget about it.
However, with the ammo counters the risk can be contained, so what we get is some people can still steadily shoot at a target in bursts, upto 600 yards, and know exactly how much more they can risk wasting.
Thus overall the realism of gunnery (at least IMO) have improved, but not to a point where people would be thoroughly discouraged to even try a shot at 400+ .
But however, since the average level of gunnery in AH2 has been brought down to a much more reasonable level, I don't have any particular gripes with it. I guess it could be viewed as a 'compromise point'. A Spit9 may land behind my 109 at 400 yards, and I still have a decent chance of outaccelerating it and stay unscathed from his relentless gunfire(unless the pilot's an ace and a pretty good shot).
I guess that's good enough.