Sinnoh Remakes At Last

To start I'm going to point out that I firmly DON'T believe that the story will end with Luffy finding the One Piece, I think there will be a little bit after that. This is mainly because Whitebeard and Rayleigh have noted that finding the One Piece will turn the world upside down, so there will likely be a considerable fallout from finding the One Piece too.

With the likes of the Yonko and at the least Kid also gunning for the One Piece, there will likely be a convergence when the Straw Hats arrive to Laugh Tale anyway, which will potentially lead to the grandest and greatest battle of the series.

With that in mind, I will rank the 3 in which is most satisfying to me as a finale, so let's start with No.3

3 - Luffy Bets his Straw Hat on the Next Generation

I'm sure we all expect that Luffy is 98% likely to not be able to return his hat to Shanks as he intends or that he will still manage to keep it under some circumstance, and will then pass it onto another like him to pass on his will. I see this probable within a timeskip of probably aged 40 Luffy in the good timeline hanging with his crew all still happy and well, so the recipient is unlikely to be Momo or Tama or Makino's son.

It works story-wise as a cyclic ending, much less bittersweet than the possibility of Luffy repeating Roger's antics that triggered the era in death, but I rank this the least because it'd feel too obvious, too tidy and would imply that all the things we don't see the Straw Hats achieve were simply achieved off-screen. I'd also worry for the fan peer pressure Oda may be subjected to if he left the possibility of a legacy sequel.

2 - The Straw Hat Pirates Disband

A sad ending it may be, but I could clearly see Luffy imitating Roger's pose in this part of the manga having completing everything he set out to do. There would be a finality in the adventure ending, not just for Luffy, but for Oda and the audience.

This would very much be a 'smile because it happened, not because it's over' kind of endings, but I rank it higher than Luffy giving his hat away because of it being a proper ending, preventing the sequel threat the previous had while also maintaining the cyclic nature of imitating Roger rather than Shanks.

1 - The Adventure Doesn't End

A cheat you say? Wishful thinking you accuse? Well I told you this was ranked on most satisfying to me, didn't I?

Finding Laugh Tale and the One Piece is a given, but do we expect Luffy to achieve his dream of Pirate King, become the freest person in the world, and do nothing with it? There's also the matter that other crewmates' dreams don't simply end by finding Laugh Tale; Nami's map of the world would be incomplete, Chopper would have diseases still to cure, there will still be more history for Robin to discover, more sea to sail for Franky on his ship, more joy to spread from music for Brook and food for Sanji, and more stories for Usopp to regale.

This is why I like this option the best, because the end of one story, one dream, one voyage, isn't the end of everything, the crew are now free to seek more; more dreams, more islands, more lies to come true

The story of 'One Piece' may be over, but an open-ended finale of the Straw Hats setting sea again, plotting a new route around the world this time, would probably be my ideal ending for them, and something more on brand for Luffy to do. While the sequel pressure is still there, in a way the open end allows the fans the freedom to make the crew's next journey(s) their own way