Oda wrote Wano at the worst time of his career. People will say that Wano opened their eyes but the truth is, One Piece was ass ever since the timeskip started and people tried to shove it under the rug because of their love foe this show.
Oda pretty much wrote the most hyped arc in his eyes at the point where he couldn't write a compelling story anymore.
Wano was doomed to fail.
I'm surprised how many people thought that after Dressrosa and WCI Oda will randomly write good again.