I think I'm realizing that part of why I love One Piece so much is that Eiichiro Oda stays true to the characters and to the themes he sets from the very beginning. Every single HUGE REVEAL he's ever done fits into what has happened, characters don't do a 180 without some really solid visceral need/want/wish that stems from exactly what they've been all along. It's integral, it makes sense, and he sets the groundwork (or uses the stuff he DID to make up the new stuff in such a way that it *seems* like he set it all up to start) so early on that I can re-watch every episode AGAIN and go "Oh, wow, he knew THAT from this point HERE!!!"
All of which plays well with Robert McKee's idea of why the big reveal, that closing of the gap between what has happened and what caused it to happen, can be so darned satisfying and is kind of the gold at the end of the rainbow for storytellers. And why the unanchored/unconnected SURPRISE! can be so off-putting.