Petition for Hiking Bear to replace Momo as future Shogun as Wano, everyone?
Given that a large portion of the story is dedicated to his aim, Momo is likely the most poorly written male character in One Piece. May well be Oda's weakest character work as an author, honestly.
Could have been a lot worse, honestly. He could have had Momo's place. At least he has more fans than a lowlife like Spandam...who has more fans than Momo.
This criticism is spot on.
I never really liked Yahiko even until the original series ended, but I agree he became less irritating as the series progresses and that his character development was at least visible.
Momo was just...there. Bland as fuck. The fact that you correctly pointed out how his best moments are carried by other characters amplify the fact that he simply is not engaging enough to drive a story by himself.