My most controversial opinion is about One Piece. Speaking as someone who adored the series and dropped it recently, One Piece really hasn't been that good since after Enies Lobby ended. After Enies Lobby, (if my memory can be trusted) every single character other than Luffy, Sanji, and Zoro seems to fall to the wayside. It gets worse post timeskip, as it falls into the familiar shonen trappings of powerlevels and new abilities. I'd argue the inclusion of haki ruined the uniqueness of One Piece's setting, since instead of cool and unique powers, we get this sort of cookie cutter rock-paper-scissors style secondary power system that kind of ruins the fun. Also, I know that One Piece has always had flash backs, but they seem to be dialed up to eleven as of the last few arcs. I don't care what this dead character did, can we please drop the ten chapter long back stories and skip back to the present to move the current story forwards?