Wano is a failure because there’s no emotional bedrock to its story. Robin was the emotional bedrock of Enies Lobby, Ace was the emotional bedrock of Marineford, etc.
It’s very obvious that the emotional bedrock of Wano’s story was intended to be the scabbards. Ask yourself seriously. Do you care about the scabbards? As much as Ace? Robin? Law? Vivi?
The answer for 99+% of you should be no. So Wano’s story has no emotional bedrock, meaning the entirety of the arc’s story is uninteresting. There’s some really hype moments, but you’re lying if you say you actually care about any scabbard or the actual story of Wano.
There’s no way 115+ chapters of poor setup and execution can be made up for.