1:I think its fine as is. For me, the balance point for all off-map call-ins is that it should be possible to dodge them if the player reacts fast enough. Any call-in airstrikes/barrages where this isn't the case should be changed so that they aren't so punishing (this is kind of what you have with a lot of incendiary barrages - quick to land but they take time to actually kill stuff).
2:It may be frustrating that your opponent dodges your airstrike and it does nothing, but it would be downright game-breaking if he couldn't. As Katitof has mentioned, the key is combo it with things that impair movement, or to overload your opponent's micro in a large engagement so they get flustered and don't react properly.
3:I also think that these abilities aren't just about what you kill. Thinking laterally, a lot of these abilities can be used for 'area denial' - to control your opponents movement. For example, imagine your opponent has a tank that is taking fire from your AT guns. Placing the anti-vehicle strafe directly behind the tank makes your opponent choose between AT gun damage and strafe damage, and he may end up making the wrong choice. Another example would be placing the anti-infantry strafe to cut off an opponent's flanking route, keeping your MGs and AT guns safe. Basically, I think these abilities can win engagements without necessarily inflicting damage.
1: Yep thats acceptable but this ability is still 'easy to dodge", and in damage very random. I stated already that even if you are in the ( really small ) target area this ability can still miss you big time. ( Meanwhile the ability user needed tons of micro, ->luck<-, and unit leading to force the veh/inf into the area in his LOS, and 90 muni even with the resource change )
2: My oly problem here that basically all units got a distinct "Airstrike" quote, and thats one of the most informating part of the game in a big fight what can and will force out an overloaded palyer froms its trance.
3: I already wrote infantry strafe works wonders. ( even outside of its range )
That tank will have tons time to react/ move out ( little bit game knowledgedge, focus is on bit ) beacuse crew will notify you that it is a plane + currently circle + that even into own base plane will take a year to arrive.