This thread has a lot of good information and all but I think most of it is only good on paper. Risking a mistimed anti air jab is not worth a potential free combo for your opponent. And guessing when your opponent times their jump in attacks is not a viable strategy for the same reason. Performing a run under, dash or walk backwards seem the most practical. But like someone posted earlier these are not true Anti-Airs. These are whiff punish strategies.
The fact of the matter is anti-airing in this game is complete ass. AA is a very critical element to any fughting game and NRS has had 3 games now to get right, only to botch it up even worse than the game's before it. Every single anti air grab in this game gets beat out by jump ins or even trades, like when the fuck has that ever happened in a fighting game, Smh.
D2 is the only universal AA that is decent, and if you're D2 sucks you are boned, Unless you play a character with a fast AA special like Cassie Cage, Raiden, Kung Lao etc..
I know where you're coming from, i don't completely agree or disagree with your post at all, but given the fact that some strategies for some characters will force a straight up routine, you can take advantage of this situation and use the other forms of whiff punishing.
Scorpion is a straight example of this, his j3 is 6 frames and works great against air to air, in Ninjitsu his B2 to be beaten out has to be with early kick or punches, in hellfire delayed jump attacks are all beaten by flame aura.
So by deafult someone who doesn't want to get stuffed by these will do earlier jumps since those can beat scorpion's options mentioned above, aside from J3 which is so damn good, if i'm not position to beat them out of the air with flame aura, i can just duck and punish them on this read, since flame aura punishes are consistent people who fall under their patterns (mistakes opportunities) can get duck punished a lot by ninjutsu and hellfire alone since they don't want to get hit by flame aura or B2.
Johnny Cage has something similar, since his ex Nut cracker is a armored AA people will to early jump ins to avoid it, which invites duck punish.
I don't think its impratical at all, its all a mater of how your character can deal with certain air attacks that they will be forced to bet to the safest option knowing is your first go to defense, while opening themselves to others