The gunnery model really took a toll on my shooting when it first changed. I was a very good shot in most situations, which accounted for my stats, as I was and still am no wizard when it comes to advanced ACM, but good SA and good accuracy in the MA will carry you a long ways. What I found changed the most was long distance chase shots. Many times with the earlier gunnery model, at d800 or even d1000, I recall constantly blasting people from the sky at that range with ease. Now, while it can be done, it takes a lot more ammo, patience, and an opponent that is somewhat asleep at the wheel. Prior to the change, once you knew where to hold your sight at certain ranges, it was easy to use 20mm or even 50's to hit guys in those long range tail chase shots. Much easier than it is now, which is likely a lot closer to reality.
So, we got an "easier" flight model, but a harder gunnery model, at least that's my opinion compared to the original game. I have no complaints either way.