Currently, the system is pretty logical to me:
If you yourself super jump: you lose the ability to call assists until you a) touch the ground again or b) take a hit. The act of
you choosing to super jump is the sole thing that locks
you out from making assist calls. If you attain altitude in any other way, you are free to call assists as per normal assist call rules.
The super jump height reset situation and your stray air-to-air hit situation are different and involve different changes. In the super jump height reset situation, your opponent gets to call assists as soon as they're free to act again since they themselves never superjumped in the first place. In the stray air-to-air hit situation, your opponent did super jump themselves, thus locking out assist calls, and Capcom decided that once they get hit, assist calls are allowed again.
Your current wording of the proposed change is:
*Assists can no longer be called after recovering from a hit after having entered a superjump state.
This doesn't affect the reset situation, because being in "a superjump state" is not about the height of your character, it is about whether you yourself super jumped. You have to address the two situations separately. My opinion is that assist calls should be allowed if someone launches you but drops the combo or deliberately resets you after your air tech recovery is over.
For the stray air-to-air hit situation it's a little muddy, and I'm still thinking it through. On one hand, I see where you're coming from. Situations like you described can happen where two characters super jump, meet air-to-air, and the character who landed the hit is in a sense punished since the other character is rewarded by being allowed to call assists. On the other hand, the current system keeps anti-air assists in check. Like people have mentioned several times, a lot of the time, people fighting AGAINST the anti-air assist reap these benefits rather than the anti-air assist user, since you can super jump and then deliberately get hit by the AA assist and then regain the ability to call assists yourself (and stall longer in the air since your air actions are reset). It also allows characters to land more safely, since you end up in situations where you super jump and because you're opponent is landing stray hits on you or hitting you with projectiles, you stay airborne for very long periods of time- in this situation regaining assist call privileges helps you eventually land (which can be difficult to do safely already).
Dahbomb mostly cares about the reset situation and you (Karst) mostly care about the stray hit situation, so I have to keep addressing both since I'm having two separate debates with two separate people.