You use the word "disappointment", I didn't. Should answer your question right there. I don't read one piece for power scaling and dick measuring contests like you and half this forum does. If he's weak, it just goes against what I thought would play out for the possible Ace character.
The "Ace" has been a conversation long before Kaido's son ever came into the picture, him having a son just adds another unknown character on Kaido's side that gives possibility to it, not to mention there was a character from the Beasts Pirates watching the events at Punk Hazard who gave orders indirectly to Jack and nobody matches his design.
That's exactly what you should do lol.
The "Ace" has been a conversation long before Kaido's son ever came into the picture, him having a son just adds another unknown character on Kaido's side that gives possibility to it, not to mention there was a character from the Beasts Pirates watching the events at Punk Hazard who gave orders indirectly to Jack and nobody matches his design.
That's exactly what you should do lol.
One Piece by Eiichiro Oda is not a complex piece of literature, there isn't ethical dilemma presented to any character at any moment, there aren't any complex characters with compelling layers, there isn't any character development, at best a character would get fleshed out.
Then there is obvious lack of urgency, lack of focus of consistency to a character's response to events, the most obvious example of it being Roronoa's rather comical response to his captain not only acting out on whims in an emperors territory thwarting what ever was left of a long term plan, but also getting arrested. It is same Roronoa who has been shown on numerous occasions showing his disapproval towards Luffy's nonchalant approach to piracy and lack of caution. Even regarding Wano itself he gave a speech to Luffy regarding the severity of stepping inside an emperor's territory and how caution is essential. But instead of providing a character fleshing out moment for Zoro, showing us how Zoro would react in a situation where his captain showed severe lack of caution and attacked an emperor head on resulting in him thwarting the long term plan and getting arrested, Oda decided to skip past that with just a supposedly comical facial expression same as any other crew mate.
Then there was another scenario where Zoro agreed to let Wano keep the Shushui and take Enma instead. That was another opportunity to flesh Zoro out as a character and show a conflict and expand upon how Zoro would react to said ethical dilemma of him earning a blade by defeating the corpse of his master with the entire "Perhaps this blade has chosen its new master" against reverence that the Shushui blade has for Wano Kuni and its natives. Instead of writing a complex literature engaging readers in how said ethical dilemma would be handled by Zoro, he decided to neglect the fact that it was conveyed in Thriller Bark that Zoro earned that blade and Zoro once again nonchalantly agreed to take Enma.
Then there is compromising characters for the sake of plot and one obvious example of it is Kozuki Oden. Just how naive is Kozuki Oden? He was dancing double crossed by Kurozumi Orochi once when he was dancing in the Wano Kuni's capital in return of the lives of hostages but he got double crossed on that. Then he saw Emperor Kaido win his fight against him by cheating and using another hostage scenario. Upon being cheated on twice by both Kaido and Orochi, it should have been enough for anyone who average mental capacity to realize neither of the men are trust worthy and use the blade he has with him to flee and attack Kaido, but no he decided to go through with the execution once again TRUSTING Kaido and Orochi to let himself and his subordinates go in the scenario where he survives an hour in burning oil.
These is just a few things from one arc and there are many many more. I do not have religious attachment to Japanese Cartoon knowns as One Piece like you do, and I can't look past severe lack of consistency and plot holes. And due to all that, I only have surface level enjoyment and I only care about moments of hype like combat scenarios and cool characters because literally that is the only thing worth while.
Anyways back to OP: Yeah have the lowest possible expectations and think of the most disappointing character you can think off. It will turn out to be a lot more disappointing than that.
