The ONLY thing that I find bad about this chapter, is how ATROCIOUS Oda's sense of pacing is.
We were on the CLIMAX of the arc, the final battles were finally getting started for real, and then he decides to go for another "side quest" to showcase a backstory.
Imagine if Robin's backstory happened not before they jump to the Tower of Justice, culminating with that amazing "I WANT TO LIVE" segment, but instead happened after the "Hunter" moment when interrupted the M3 fights.
This back and forth with different pacing is really bad.
It works in books like A Song of Ice and Fire because they were written precisely for this kind of shenanigan to work there, but here it just feels shitty. Chapters that otherwise would be ok or cool, end up getting A LOT of hate just because they come and interrupt far more exciting stuff that were going down, for no reason at all. I never liked these "middle of fight backstories" and the way that Oda cuts the rhythm of the narrative with them.