Like if you think about it, the vast majority of interesting plot-threads set up in Saobody - Marineford and in the early Post TS haven’t actually payed off.
None of the supernovas other than Law have had satisfying stories, we still don’t know anything about the void century, we’ve barely seen tons of the character we’re interested in (Shanks, Blackbeard, Mihawk, Aokiji, etc), haki is incredibly convoluted and underwhelming, no new ancient weapon stuff in the last decade, etc.
Dedicating so much of the story to BM and Kaido after we already had a more interested overarching story established was a bad move writing wise.
Likes there’s a reason why so many people like Zou and the Reverie but not WCI.