Lot of things been mistakes.
The worst part things who been actually interesting(like Oden vs Kaido battle, plot about Ryuma sword, Jack vs Inuarashi/Perospero vs Nekomamush, Kaido flashback and more things) are rushed or complete offscreen but irrelevant stuff was shown(udon,Tama plot,running, running).
Oda didn´t had a good balance.
Imagine we got 150 chapters+ and all what we got for Kaido is a half ass flashback.
Let be honest the Oda in his prime(alabasta) would finish off the arc under 70-80 chapters.
He added to much irrevant stuff and cut off relevant stuff for case.
I never saw him writing such bad as he did in Wano.
There are no arcs I have under 7/10 in One Piece, even Punk hazard or Dressrosa(this was similar to Wano but at least little more better) or Whoe Cake island because I feelt these arcs at least had a good proper writing/pacing...
Wano is maybe the only arc where I would give something between 5.5-6.5 because it is really not that good.
It has also his amazing moments, but it wont change my view in general of this arc.