What if Oda is preparing for a big tragedy towards the end of Wano that both the Straw Hats and their close allies outside of Wano (Sabo, Vivi, Hancock, etc) will experience now that 2 Yonko have been taken down in the New World?
Wano shares similarities and parallels to Water 7 Saga arcs like Enies Lobby and Post-Enies Lobby. Enies Lobby is the pre-timeskip arc that had the Straw Hats gain the most new power-ups they’ve ever gotten in one arc so that they could overcome beating the strongest opponents they’ve ever faced at the time.
In the Post-Enies Lobby Arc, we had a grand party, new Straw Hats, etc… Towards the end of Post-Enies Lobby, a tragedy happened outside of Enies Lobby with Ace being beaten by Blackbeard and taken to Impel down.
Similarly, Wano is the post-time skip arc that had most of the Straw Hats, especially the Monster Trio, gain the most power-ups they’ve ever gotten in one arc so that they could overcome beating the strongest opponents they’ve ever faced and to reach the level of an emperor-tier crew.
In Post Wano, we’ll have a grand party, possible new Straw Hats (at least Yamato), etc… Towards the end of Post Wano though, I think there will be a tragedy involving the people outside of Wano that are close to the Straw Hats, similar to the events of Post Enies Lobby.
But since the Wano arc was the darkest and most oppressed arc for the citizens in all of One Piece history, as well as the accumulation of a huge battle against 2 Yonko after so much build up, I personally think both the Straw Hats and their close allies outside of Wano (Sabo, Vivi, Hancock, etc) will experience a big tragedy as soon as Wano arc ends. I just think that there does need to be a big tragedy in the New World for the Straw Hats to experience eventually. But I think that a tragedy happening before Wano country ends, with the expectation that the citizens and alliance can survive the tragedy, is impossible at this point. Given how broken the citizen’s spirits/willpower are and since they aren’t powerful characters, if they receive news that the people who attempted to fight against Kaido and Orochi lost, then the citizens would all commit suicide at that point.
Since the focus of the story will shift back to the Straw Hats towards the end of Wano, I think it would be a lot more impactful for the Straw Hats to achieve this milestone of beating these Yonko crews after so much buildup, only for them and their close allies outside of Wano getting captured or kidnapped by the World Government, Admirals, Blackbeard, etc.
These types of events could be what happen at the end of the Post Wano arc after we’ve celebrated the defeat of Kaido and Big Mom.
*Theory by 1abfree