I'm no Yonko fan but the way admiral fans are acting like an admiral can take a Yonko because an admiral neg diff'd to injured commanders is ridiculous.
Kaido was defending against Law, Kid, Zoro and Luffy can you see any current admiral doing that?
Akainu is the standout. Guy is a beast mind.
In 1v1 combat, Akainu is tops. Fujitora terrifies me, though, in terms of long-range attacks, because he can literally call down a meteror shower. Even Kaido is going to have trouble defending his territory/crew from a damn meteor shower. Akainu can do long range attacks, but not on that level. If I need to assault a pirate fortress, I want the meteor-shower-man, honestly.
I think what Oda's trying to show here is:
In terms of offensive power Admirals = Yonkou.
It's defense and endurance where Big Mom and Kaido wipe the floor.
Base Inu and Neku each 1v1d Jack, a YC3, to a standstill, wrecked him in a Sulong 2v1, and then Inu low-differed Jack once he could use Sulong.
Sulong Inu and Neku did almost nothing to Kaido and then got stomped, while being supported by: a ninja who can absorb then release forces of nature; a man who could cut fire (helpful against a dragon); a man who blocked a murderous, powerful attack from Zoro straight up (Denjiro), a man who had once fought Oden on somewhat equal footing (Asura); a marksman who shot King's sword out of his hand (Izo), and then Kiku and Kawamatsu (uh... not many feats here).
Base Scabbards slot to being around YC3 level/Jack's level based off of this information.
Kaido was ripping through 8 Samurai around as strong as Jack. I know we mock Jack, but the guy fought Inu and Neku in 1v1s for, what, 5 straight days? Kaido's durability is on a completely different level compared to anything we've seen in this series, he crushed 8 YC3s, after allowing them to get multiple hits in, and they only left surface level wounds that didn't even scar him.