I'm probably alone on it, but I really don't like the Fishman Island arc. Like, at all.
I think it has to do with two things. First is that most of the main characters seemed to get Flanderized, even moreso than they already were. Nami is now explicitly "the ****", Chopper is way too kawaiidesudesudseuiduseikjhfdjjdjhkjhkj (whereas before he was kind of cute, but was cool when he got serious), and Sanji if Mr. Hard-On. Oda rushed into the arc way too fast; when he should've spent a few chapters explaining the TWO YEARS of training they went through, and important things (like how Zoro got his scar, why Franky looks so different, or how the **** Luffy has managed after, you know, his brother died), instead, he spent a chapter or so focusing on...undersea currents.
Yeah, **** character development and exploration, let's learn about science in a world where it rains ****ing lightning.
The other problem I can best describe as the arc being too similar to Skypiea. They go to a hard-to-reach location, and when they get there, they're almost immediately treated as enemies for an incredibly stupid ****ing reason. It turns out that there's an internal conflict going on with the island that has been going on way before the Straw Hats got there, there's a flashback that literally amounts to nothing (similar to the Norland flashback in Skypiea which, as sappy as it was, added pretty much nothing that couldn't have been stated in a simple "They were friends, they're dead, **** sucks"), and the Straw Hats' involvement isn't crucial, and it's more like they're intruding on what's already going on. Compare to one of the better arcs like, say, Enies Lobby. They're don't just "happen to be there" in that arc; they're there to save Robin, and it's incredibly personal. Here, though, there's only a conflict with them because **** if I know.
It felt like he took 3 steps forward with the Impel Down and Marineford Arcs (by giving a lot of villains development, as well as a huge amount of payoff with the giant fight in Marineford), but then 5 steps back here.
All I'm praying for is that, after this arc is finally over and done with, Oda just slows things down a bit and has a chapter or two of them talking, explaining what happened over the past few years, changing clothes out of what they've been wearing for what's probably been days (I will never get used to Chopper's new hat, ever; it's ****ing ********), and remind us that they're actually characters, not "da cool peoples who do da faighting and are funneh and sum has ****