Imagine if Oda stuck to his idea of Kaido being a guy who loves fighting strong guys, bored with life. We would see him sporadically appear in places where top places are and fight them in the background while the Straw hats advance through the new world.
I think him being a straw nihilist would have fit his character:
1. Erase Orochi and renamed Kaido as Kurozumi Kaido. As a kid, he lived in fear as an Oni with his family and their race in Wano, because Onis are treated as sub-human there despite being physically strong. His life was hopeless.
2. What happened to Orochi's family eventually happened to Kaido's: being murdered for the fault of someone who shared their family name. His parents sacrificed themselves to sail him out of Wano, but he never forgot about all this.
3. He got shipwrecked in a warring nation and started living as mercenary. He hated the world for what had happened to him and his family, and felt the urge to kill and kill more to hurt the world back since the world couldn't be changed.
4. In his journey, he met Xebec who wanted to become the King of the World. For the first time, he felt like the world could change, and asked Xebec to make him an apprentice on his ship. Xebec said yes.
5. However, as we knew it, Xebec eventually failed and died in God's Valley. Kaido got captured by the Marines and Xebec's death haunted him, because it proved to him that the world couldn't be changed. The WG tried to execute Kaido numerous times and failed, so they sent him to Punk Hazard as a research specimen. He began fixating on one idea: if the world could not be changed, he should destroy it so the world can begin anew.
6. In PH, he got to know King, who shared his hatred for the world (since his race got wiped out). They eventually broke out of PH and started the Beast Pirates.
7. After recruiting Queen and Jack, they got back to Wano. Rather than making a fool out of Oden and Kaido like Lolda did, simply have Kaido beat Oden fair and square in a duel. The rest of Kozuki storyline followed what Lolda wrote.
8. Kaido made King the governor of Onigashima and Wano capital, while Queen managed their lab and prison. Jack became their field agent like in the story.
9. Kaido began researching a way to destroy the world and found several options: starting a war large enough to engulf all of the planet, using an ancient weapon to do it, or finding the One Piece and using it to destroy the world.
10. This means, Kaido being defeated by the savior of the world like Nika also served to prove Kaido wrong, in that the world could indeed be changed. Just not by Kaido. His pirating career grew to be an empire as his means to his world destroying end.
Just my two cents.
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@MonsterKaido