I'm very sorry to have put 5 to probably one of the biggest cornerstone of shonen history, these are my motivations tho

One Piece starts off as one of the greatest shonen ever written, the characters are good even if cliches and the story stretches over tens of volumes and kilometers in a pirate world where the greatest thing to be found it's not the one piece but the freedom for yourself and your friends and companions.

One Piece stays great for very long arguably it stays very important even after the time skip (let's say that Rufy challenging Big Mom in Fisherman Island it's a great ending of the good part of the manga), it is very well drawn in the beginning at least concerning the page layout and how the visual narration take place (in the beginning some of the fighting may resemble Toriyama's awesome fighting in the first volumes of DragonBall).

the first part of One Piece it's probably a 10 not because it's the best written manga over there but it sure is an emotional well thought and incredibly important one, the second part of One Piece is probably a 1 that's why i put the 5 star rating, now i'll (very shortly) talk about what's wrong with these new chapters.

Oda seems to have completely forgotten of what made the first part good, he can't draw anymore, he relies on splash pages where something big happens and he just fills them with close shots of the characters usually reacting to this event, he tries to fool the reader with fake deaths and repent in like 2 chapters where the character involved is still fresh and strong, no drama anymore, at least no real drama, only pathetic one like the social and political background of let's say Dressrosa or Wano, nothing comparable to Nami's background story or Sanji or the first meeting with Zoro, or let's say the time he rescues Nico Robin. Not only this he also tries to slow down a manga that has already reached almost 1000 chapters adding useless and shitty chapters no one cares about on maybe some secondary characters doing nothing. He still is able to do something good (the mini saga of the reverie or the flashback with Gol D. Roger) but he just cares in stretching the bore out of us.

I don't know what happened if it's an editorial choice based on the sales of the manga or if he doesn't want to let go a great opera that's going around for years but please Oda let's take us back to the freer man in the whole see and to that promise between Ace, Rufy and Sabo