The problem with manpads and AA in general isn't lack of skill or whatever, but that the flares for aircraft currently are utterly broken and have been so for years. When it comes to jets, the AA guy doesn't even need to lock on to the target to take it down, just a flare will do. When a jet itself gets locked and missile gets launched before the pilot manages to pop flares in that 1ms window, the jet will die 95% of the times, no matter how many flares gets popped afterwards or whatever ridiculous manouvers the pilot might pull off. With helicopters, it's not "that" bad, basically being equal to someone flipping a coin in the background after each launch, giving it 50/50 chance of being hit or miss.
(A little fun fact about bots not firing the rocket when they "lock" you - The locking sequence begins the moment the AA guy starts looking at the aircraft, even if the weapon deployment animation after switching weapons hasn't finished yet. That's where that "window of opportunity" to pop flares comes from, since the bot has just swithed to the launcher and can't launch the missile for another second or so because the animation hasn't finished yet.)
How does adding extra AA make the game more teamwork oriented when it comes to air assets, es specially CAS, when it is so broken already? No one ever lases anything, or if they do, it either happens once in every 10 rounds or the guy lasing can't do anything because he gets tapped the second he tries to look at anything. Lases for jets don't lock anymore, so the pilot has to manually guide the bomb towards the target. Some maps, like Thunder are utterly unplayable for CAS because you can't see anything because of the fog and if you go to low altitutes, you get instantly tapped my some random manpad in the forest. I don't think I've seen the F15 on BG large survive for longer than 5 minutes and that damn thing has like 15min respawn or something while having to compete with insane amount of AAVs and Quad guns in addition to the manpads? In what universe is that concidered fun?
The issue isn't about lack of teamwork or maps being unwinnable, but more of how god damn frustrating is to do anything with aircraft. It was already frustrating to die to some random shilka that one tap sniped you from 2km away, but now pilots have to dodge the utterly broken AA missiles from every random location on the map where the bots might wander to. Instead of making the game even less fun than it already has become, how about just enforcing the rules more forcefully to restrain people from bombing stuff that's nowhere near the frontlines if that's the reason manpads got added? We already have a rule for it, it's just almost never enforced.