Why did Zoro come to Onigashima to slay Kaido?
Who has challenged the dragon in dragon twisters?
Who has inherited Enma, the blade that gave Kaido his only scar and the blade that cuts to the bottom of hell?
Who has taken a swing at the dragon in the same dragon-slaying style like Ryuma did?
Who carries all the burdens of the samurai on his shoulders that are mocked by the dragon for being weak?
Who can restore the fear of the mighty samurai that protected Wano for centuries?
Who has Zoro been targetting the whole raid?
The story has done more than enough, it only has to finish what it started.
Of course it does, probably much later on, after Wano. Orochi isnt the only snake in the world.
It was never supposed to be epic death for Kaido but an epic world-shaking feat for Zoro so his name reaches the heavens.