1. The
Scabbards. Only ones we really needed for the plot to progress were Kinemon, Kanjuro and Shinobu.
2.
Oden. Enough's been said already.
3. The
Vegapunk satellites, like what was even the point? The only one who served a major and interesting role was York, but that was short lived, while two others died before they had any real impact, and the rest just standing around or serving as fodder.
4. The
Orcohi Washing Banshu whatever
ninjas, the
Mimawarigumi and the
Yakuza region bosses. I don't think anyone bothered to remember these groups or the names of their members lol.
5.
78% of Big Mom's fodder children who don't even maintain a consistent theme beyond dessert names and aren't even that diverse, with 70% of them being mostly humans despite claims about Big Mom marrying into different races, which was a missed opportunity for introducing more new races beyond snakenecks and three-eyes. We don't even get any cool one-on-one fights with them beyond Cracker and Katakuri, and Smoothie was just sort of... there. And Tamago isn't even a child or an ex-husband as far as we know. Also screw Bobbin and that one guy who thinks he's a train too.
6.
Germa 66 felt poorly executed, with Oda not even giving them a proper conclusion or fight with Sanji and instead relegating what should've been their fight with Sanji to Queen. Even theirs and Big Mom's plot made barely any sense.
@Borasey79 wrote a pretty awesome alternative of what Oda could've done with them while giving them more ties to Vegapunk, which just goes to show how much of a missed opportunity they were.
7. Not a character, but Pudding and Sanji baking a
cake for Big Mom that accomplished nothing except saving her life, putting the lives of their allies in jeapordy and saving the lives of their enemies was a huge waste of panels.
8.
Yamato. Honestly, it wouldn't be so bad if Oda had introduced her from the start of Wano instead of at the last minute where the plot could've played out the same without her. The fact that she wants to emulate a character I like even less just makes her feel even less interesting for me at least.
9. The
Straw Hat Grand Fleet has been a pretty big disappointment so far aside from Leo and maybe Barto since they haven't had much relevance since Dressrosa and they haven't bothered to recruit any new members either because lOda is too obsessed with maintaining his unamusing japanese number pun obsession.
10. I hate to say it, but Chopper and
Usopp have greatly declined as characters, with Chopper becoming a mascot whose only their for quick healing when its convenient for the plot, and Usopp regressing as a character in every possible way and getting stuck with a very uninteresting combat style. Brook also hasn't seen much interest, but I'm hoping Oda ties the kingdom Brook grew up in to the main plot.
11.
Carrot. I love the character to bits, but she ultimately served no greater purpose in the end and didn't even get a proper sendoff by Loda. Even the Minks as a whole have been bloody useless, along with their fatass elephant who just stood around hyping up Nika for a dozen chapters before leaving and doing nothing. The dukes were kind of useful but they became bland and annoying by the end, and their role as members of Roger and Whitebeard's crews only amounted to them just popping up at random points to give stupid grins and say they stowed away when convenient.
12. The majority of
vice admirals.