Probably the biggest flaw of this show, and perhaps the other big 3 shounens as well, is that nothing is ever at stake
Although One Piece might parade around the consequences, nothing actually ever happens that has any lasting negative effect.
Every arc is 'and they lived happily ever after, until the new island where we repeat the exact same shit for another 50 episodes'
Take the water7 arc for example. Usopp should have probably died after the Franky House beat the living shit out of him twice in a row. But, he miraculously survived. Ok, whatever. And then, after getting in an argument with Luffy, he takes several full power hits from Luffy on his skull and abdomen.
Yet, Usopp survives and eventually rejoins the crew, after burning as many bridges as possible. And this is the main issue:
Even if the show might try to convey that something is at stake, it all works out to be exactly perfect and everyone ends up happy. They get to eat their cake and have it, too.
There's literally no tension in Dragon ball, Naruto, Bleach, or One piece, because no one of importance ever dies unless they're a bad guy. The only time good guys die is when it's a fucking flashback in One Piece