I think the thing that bothers me the most about One Piece, when I look back on it, is just that the timeskip feels like it lacked significance. The separation of the Straw Hats was a huge and heartwrenching thing, Luffy was on his own for ages, they hyped up the years of training so much.
Then they reunite to.. virtually no fanfare. It was like they were never apart. I wanted EMOTION. This series knows how to tug at the heartstrings. But they picked up like no time had even passed. Two years of hardship swept under the rug. Luffy's horrible time in the war, never mentioned. No indication of real joy that they were finally reunited. No Luffy prostrated on his hands and feet, promising that he'll never allow something like Sabody to happen again, showing some kind of character growth after all these events and all this training. There could have been a whole mini-arc dedicated to the intra-personal realities of their sundering and reunion, and instead it was just a joke arc with the fake Straw Hats and then "welp we're back together, on to the next island." And they went to the next island, and never spoke of it again. It was the biggest build-up-letdown ever. Especially since no one really even feels any stronger. Luffy/Zoro/Sanji vs the Pacifistas was literally the only glimpse. Then no one did anything impressive ever again. And now it's been so long that any potential superhuman feats are so far divorced from the timeskip that they just feel like normal arc upgrades.
OH WELL.