His potential ceiling, if left to grow, which is why Kaido wasn't going to let Luffy grow.
That is more saying he will die and so never have the chance to become that strong, not that because he is fatigued he can't use adv CoC, Kaido's absolute shock and horror at Luffy having it don't line up with what you are saying at all... 死に損ない
Kaido's shock and horror is at Luffy using it
despite being that roughed up and close to death. It is in no way related to Zoro like you make it out to be. Kaido already acknowledged Luffy's Conquerors Haki in act 1 and Luffy's ability to eventually surpass those Great Pirates in combat by virtue of his Conquerors Haki in ch 1001.
It was an air slash (cut) infused with adv CoC, surely that should leave some sort of permenant scar on a human, if someone far weaker with far less visible "adv CoC" (in your mind) than Roger can scar Kaido merely by the virtue of having it be "advanced". The cut got through and hit Oden, even if partially "blocked".
Oden, the person who withstood boiling in oil for an hour and the person who is proclaimed as a monster, got throttled by that air slash and was sent flying into the other side of the Island. And the cut didn't get through to Oden, what got through was the compressed air that Roger sent using that Air Slash, which threw Oden back.
Punches have deformed peoples faces, before, when has Zoro's blade EVER scarred someone before Kaido either? It's plot, otherwise Mr 1 would have a giant scar from Zoro, as would all of his enemies.
Zoro has cut almost every opponent of his and they have bled visibly in panel. Ofcourse its Oda's choice to show the scar or not when we meet the character again. You're acting like its only plot when Oda made sure to give narrative importance to Zoro cutting Kaido by giving him a powerup for that specific event from the start of Act - 2. The way I see it, you're just refusing to admit that Zoro scarred Kaido and recreated Oden's feat.
Zoro didn't "recreate Oden's feat", he created a much smaller single scar on a less durable form, to a Kaido that was underestimating him rather than fighting him with full focus.
His scar is on a canonically stronger Kaido on a more durable form, (unless you're gonna argue that Hybrid < Dragon). He also did it despite shattering more than half of the bones in his body. It was thematically meant to show Zoro recreating if not rivalling Oden's feat, no matter how you want to downplay it.
Let's also entertain the possibility that Zoro did not use adv CoC there.
So you mean to say that Zoro, using just armament haki and ashura, was able to recreate the same feat as Oden (who did it on a much weaker Kaido (confirmed in the manga) and used advanced Conquerors Haki (confirmed in the recent vivre cards)), using just his raw strength?
:yasu: