I suppose I’ll put in my two cents…
The best use I’ve found from this hyper is to DHC into a better hyper. For example: Phoenix/Dark Phoenix is teleporting in on Taskmaster. Taskmaster is on the ground on player 1 side (the left). You can see the start-up of Phoenix’s teleport and on reaction input :qcb:+:l: and what will happen is: if she teleports behind task, task will punish her with legion arrow. If she teleports above task or in front of task, task will start up aegis counter which can then be DHC’d into another great punish super. This should only be taken as an example however, because taskmaster has a better option select in this situation which is simply +:h: which will punish any teleport but the overhead teleport but will allow task to deal with that relatively easily. (just make sure task isn’t staying too still or phoenix can use her fireballs to stay safe in almost every scenario)
Other uses for aegis counter are gimmicks. For example, with 4 bars and Akuma second one can use taskmaster’s charging star command normal +:h: to hit the opponent and immediately input aegis counter. If the opponent didn’t block, you can immediately go into Akuma’s beam super. If the opponent did block, you can wait until the opponent leaves hitstun and immediately input raging demon which they won’t be able to jump out of from that range (same concept works for Haggar, not sure about Tron or Thor).
Otherwise I find the hyper suitable for only very, very specific situations such as Tron or Haggar jumping in with an active attack or Spencer trying to bionic arm a whiffed normal. Just make sure to watch out for DHCs if you’re trying to counter a super.
So as a breakdown…
What it’s good for:
Gimmicks that probably won’t work on the same guy twice
Punishing very few situational hypers/jumping normals
Punishing sentinel’s hard drive
Baiting Spencer to use bionic arm by shooting arrows at him
What it’s bad for:
Trying to punish any normal incoming from the ground
Trying to punish any normal incoming from the air with VERY few exceptions (sentinel is not an exception, do not try to punish sentinel’s air normals)
Trying to predict normals
Using in general