1. Oden
Glazed left right center by the entire village, townspeople as some hero. In reality this Mary Sue self-insert incompetently sold out his people, a gullible leader is no leader at all. Abandoned his country and people to go on some silly nilly adventure, worshipping the false virtue of "freedom", this man is the ultimate fraud.
He isn't even fun to make powerscaling discussion with, existing in this odd in-between range of high-tiers and lower top tiers that is increasingly being power crept arc after arc. The least Oda could have done imo is give him a devil-fruit or something because honestly playing match-ups with weaker characters like Pica and Cracker is much more fun than this weird Hakiman
2. Crydo
Lee summed things up well but the only person who could come next after Oden is the guy who sneak attacked and held him hostage.
Older audiences who have been around for a while cannot help but reflect on the hype this guy had even back in Punk Hazard. His reveal shook the fanbase and even his underlings such as Jack had a strong following across the base, anyone remember #MammothBoyz?
Suffice to say Crydo's hype-to-return on investment is a 10:1 ratio; he didn't kill any Scabbards and the possibility for him looking anywhere near what we would expect of Primebeard or Roger died when Big Meme came to the island and cut his workload in half. I like technical, creative fights and Crydo playing baseball for a year was anything but that.
Not to mention, 0 character. Kaido is an NPC, Queen carried the arc character wise lol. Much more entertaining and unique and we didn't even see Queens backstory
3. Vegapunk
20 years of anticipation, it didn't pay off. Oda has a terrible habit of giving a character years worth of hype in the form hearsay and town-talk and it is unfortunate that all we got from Vegapunk was a perverted old man, gifted with the greatest mind in the world, yet cannot even discern basic ethics.
He instead sits the fence in labeling the Gorosei's global genocide something he cannot call good or evil, morally grandstanding above the now shocked and frightened world, considering their reactions as of ignorance and a failure in holistic reasoning, when really he is just a dumbass.