I feel like Aegis is somewhat underwhelming relative to perception. I may be somewhat alone on this, but it's 3 things for me:
1) Mythra's big gimmick in neutral, the thing that's letting her get away with spamming aerials on shield, is the extremely low hitlag on all of her aerials. Those of us who've played Brawl are no strangers to dealing with this, however--this is exactly how Brawl Marth was. Adequate counterplay to these low reactability windows has been established over the last decade, so I feel confident in saying that people are going to get better in not letting Mythra run aggressive trains on them in neutral. Right now, Mythras are playing like she's Roy, but they'll eventually have to start whiff punishing things instead of aggro'ing everyone. Mythra's good at whiff punishing, so this isn't entirely a bad thing, but right now she's getting away with both, which makes her seem really overwhelming in neutral.
2) Their disadvantage is worse than you think. Their recoveries are, in some matchups, worse than Little Mac recoveries. Pyra's up-b shenanigans at ledge are fake and you should be trying to hit her every time, even if you failed to intercept. Photon Edge is just a skill check, and most characters should have some way to spike it or kill Mythra for going for it. Lack of ledge mixups means that sometimes they just don't want to risk drifting to ledge to avoid a juggle. On top of that, Mythra's rolls and spotdodge data are more punishable than normal, so even if they get off the ledge and/or land safely, getting out of the corner can be hard.
3) I think their advantage state isn't as good as it looks, though it is pretty good.
At low percents, Mythra will get you from 0 to 30-40 for free, but, well, that's most of the relevant cast right now in one way or another, so that isn't particularly impressive. At mid percents, I think Aegis runs into some problems. Outside of Pyra low d-air to up-smash, they're not killing you from center stage, and they're not going super deep to edgeguard you, or super high with a Pyra up-air/n-air, so that means that the scariest thing that Aegis has at most percents is ledgetrapping. While Mythra is really good at ledgetrapping, her setups aren't usually lethal. She can cover roll and neutral getup simultaneously with d-smash or something, but back hit of d-smash won't be killing you if you roll, so unless she reads the roll super early and f-smashes, you aren't dead, and even if she does that, you still aren't dead since it'll likely be cross stage.
Pyra ledgetrapping is much more lethal but riskier for the Pyra. If she misreads an option, like going for a ledge jump read or shielding near neutral getup and foregoing the roll coverage, she risks losing stage control, and losing stage control as Aegis is really bad as we see in #2 above.
I think that they're in the top 20 range, but it's hard for me to see the claims of "obvious top 5." I'd like to see Tweek play them.
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