But it doesn't change the fact that this new haki will have played a determinat role in Luffy's defeat of Kaido and is the sole reason/key of why Luffy even started to truly hurt Kaido. It seems the way to go, it's the key for him to bring Kaido down.
And even Kaido says that what Luffy needs to do is to refine his crude technique with it.
In the scenario @Fleet Admiral Lee Hung described about all the Advanced CoC users in the future, I see a dehype for the figure of Kaido and the buildup to take him down.
That's mainly because we experience the world from a Luffy centric perspective though. Even before all that happened it was generally assumed that most top tiers would have a very tough time against each other, so if most or all of them can make use of that ability, which is the bare minimum to even fight against Kaido and damage him, it wouldn't really be that surprising in hindsight.
And btw I absolutely don't see how it would dehype him in any way. Far in contrary to that it will only hype him up, if others later on would get completely wrecked by these sorts of attacks. I think that Kaido's feats -those he already showed- are already "timeless" and won't be outdated, cause that's already the peak of tankiness. It imo can only be surpassed by himself via a potentially incoming awakened Dragon Devil form, which imo will be the thing, that really sends his hype through the roof (WSC), similiar to how I see Luffy's body enhancing quirks now becoming his key ability again.
Imo that ability rather equals the playing field.
And like I said in my post, not everyone will automatically align their arsenal towards their haki game, even if it's that powerful. I mean take a look at Big Mom for example. "Fulgora" was super impressive. I can see someone making a case for her all out homie game being more powerful than her advCoC game. Basically: I still can see how a lot of devil fruit abilities will simply be more valuable, even if it becomes a "common" ability -which is still just a possibility btw-. A lot of stuff that can't kill Kaido, can still kill anyone else in one go afterall.
I can easily see a guy like Kizaru being superior to the average advCoC game, if he goes all out with his light fruit for example.
If it gets more common that ability will just elevate the whole tier as a whole even higher. And again, perhaps those CoC attacks are not even the absolute peak in terms of haki game, perhaps there's even more to come.