Return to Sabaody: 8.0/10.0. Solid introduction arc for the "second half" (actually not really "half", but it can be considered it in a storytelling sense) of the series, it shows that the strawhats are more than ready for New World (not really to face the Yonko, but at least to not die or face grave injuries like Kid, for example). Not a 9 or 10 because it doesn't really show much of the strawhats interactions (they reunite after 2 years and it's like it was just a weekend away), something that will become a bigger problem in the next arcs, and I disliked most of the new designs (goodbye, good ol' Franky... 😢).
Fishman Island: 5.0/10.0. Actually a tolerable arc in a binge reading, with some good moments here and there (Luffy knocking out half of the enemies with his haki, Shirahoshi revealing her powers as the Ancient Weapon Poseidon, Jinbe donating blood to Luffy, Big Mom's crew introduction, etc.) and addresses a pretty relevant topic, further elaborating the hate we saw from Arlong (the racism against the fishmen and the resentment of many of the fishmen towards humans). The problem was that Hody and his goons weren't really that good villains (they were basically Arlong's crew 2.0, but without the charisma) and Oda started his post-skip trend of introducing a bunch of useless characters (Shirahoshi's brothers, most of the New Fishman Pirates, Neptune's ministers, all looked like filler characters). Fishman Island could've been easily 20~30 chapters without all the stalling. It's probably also considered one of the worst arcs because everyone was too eager to see the New World.
Punk Hazard: 6.5/10.0. Okay arc for an introduction to the New World. You can kinda make a parallel with Little Garden, Caesar is just a lackey for the bigger villain to come (DoFlamingo), just like Galdino was to Crocodile. It's not a great arc due to similar problems to Fishman Island (unappealing main antagonist, unnecessary stalls, a few filler characters, etc.), but have better peaks (e.g.: Vergo vs. Law and Smoker, Aokiji's first appearance in the New World, etc.).
Dressrosa: 7.5/10.0. This is the best long arc of post-skip, IMO. Great main antagonist and had some fantastic moments (e.g.: Corazon's flashback, Franky vs. Señor Pink, etc.), but isn't great due to the same problems that started in Fishman Island and got amplified here (a pile of unneeded characters, run piece, stalling some fights, etc.). Adult Sabo was introduced here too; at first I wasn't that happy with it (seemed just like a compensation for Ace's death), but after the time has passed I can understand why an "Ace 2.0" was needed in the story.
Zou: 9.0/10.0. It's a great short arc, one of the best of the entire One Piece. I liked the Mink Tribe in general, especially their leaders (Inu and Neko), and their standing against the Beasts Pirates to protect Raizo was one of the best moments of the series. The introduction of Jack put a lot of hype in the Beasts Pirates; I know that, at the end, he was disappointing, but at first he seemed like a ruthless monster who had guts to even face an admiral and the former fleet admiral. The are also some key points to the story, as the introduction of the Road Poneglyphs (the main poneglyphs of the Rio Poneglyph, the true story mentioned by Robin back in Arabasta) and a better showing of the Voice of All Things.
Whole Cake Island: 3.5/10.0. I think it's the first awful arc of the series... the beginning of the "end" (quite literally too, as the strawhats start to face the Yonko more directly and thus are already seeing the "pot of gold at the end of the rainbow". We have some key points to the story, as the appropriation of Big Mom's Road Poneglyph, but it honestly felt like a filler arc to me. Most characters were uninteresting (all the villains besides Katakuri seemed to be really bland, even Big Mom looked like a mindless grunt with just strength as a pro). It was an arc for Sanji's development, but I felt that he shouldn't have had these kind of problems at this point in the first place(he distrusted his own crew because he felt that they wouldn't be able to face Big Mom? C'mon, Luffy already declared war on the WG, the strongest force of all). Even Luffy vs. Katakuri left some poor taste, as Katakuri was supposed to be the main protector of his family, yet he still gives an advantage to his enemy by stabbing himself. That's the mc's plot armor at its worst. The Wedding Cake plot device was a huge bs too (probably the worst stall the series ever had). Only Luffy vs. Katakuri, Luffy vs. Cracker and Bege seem to be the strengths of this arc.
Levely: 8.0/10.0. Great short arc with a ton of lore. We finally see a Levely with detail, we get better showings of past characters (Vivi, Shirahoshi, Rebecca, Dalton, Kureha, Wapol, Mjosgard, Lucci, Kaku, etc.), we see the destiny of Kuma after Sabaody (and become aware of Bonney's connection to him) and we finally meet the overarching antagonist of One Piece (Imu). Shamrock also first appears, but is initially thought to be Shanks (then the "evil Shanks" theories start to gain weight). And we finally meet the main revolutionaries.
Wano Country: 2.5/10.0. Probably one of the most anticipated arcs of post-skip alongside Elbaph, but ends up as a horrible mess. It feels a bit like Marineford, but even more ruffled and with a massive amount of unnecessary characters. Oden's flashback was incredibly disappointing and Kaido was as disappointing as Big Mom (just another mindless grunt). Most Wano characters were dull IMO (most Red Scabbards, Oniwabanshu, Yakuza, most Beasts Pirates... please, go away). I'm also on the team that considers the Nika's retcon a bad move on Oda's part, so it adds up to the train wreck. Luffy's just a "chosen one", a pretty standard shonen mc. Despite having an important flashback to the story, we have almost no lore revealed. The Onigashima's fights were mostly good, Yasuie's sacrifice was striking and Marco's appearance was dope, but that's it for Wano.
Egghead: 7.0/10.0. I know that many people dislike this arc, but it's actually pretty decent for me. We finally meet Vegapunk, the world's greatest mind (although with some glaring flaws), we have a pretty good flashback with Kuma/Bonney (it was just too short for its importance) and we finally see Luffy facing an admiral evenly. We have the Gorosei finally showing their abilities and we get a good piece of lore from Vegapunk and Saturn too. The side incidents of Shanks vs. Kid and Blackbeard vs. Law were great too. If not for the usual stalling, Emet's bs plot device and Vegapunk's bs death, that would be actually a better long arc than Dressrosa.
Elbaph: ??/10.0. Still running, so I won't give a score yet, but it would be an 8.0 so far IMO (it would be the best post-skip long arc if it ends up like that). We have a better development of Elbaph's story, many interesting characters introduced (Xebec, Rocks Pirates, Harald, Loki, Gaban was properly introduced, et al.), an amazing flashback with the Rocks Pirates (it took a hit in the latest chapter though), a nice piece of lore roaming around (e.g.: the Harley), among other things. Things can always go downhill though, so better wait to see the end of it.