@Deicide:
I’m telling you. Next arc is Mary Geoise. We’re going there because of Hancock and/or Sabo/Vivi. We get to meet Bonney, help save Kuma, then lead to Vegapunk to try to fix Kuma and destroy the SSG. Lots of hooks for Jinbe (slavery), Robin (Revolutionaries, CP0) and Franky (technology).
Like I mentioned in the other thread, I really don't think we are heading backwards on the Grand Line (yet). Geographically, the crew is probably 80-90% of the way to the end already, there's no reason to cut that trip short, especially when much of the reason for this story is the actual trip (Oda made a huge deal about them reaching Red Line after Thriller Bark).
Also, we gotta wait and see what happened to those three. I'm not counting on any of them actually being captured and Oda repeating yet another Marine/WG rescue arc after Ace, at least not until the final war.
Additionally, there's pretty solid proof that Vegapunk doesn't reside at New Marineford or Mariejois, just based on where Fujitora and Smoker are/were.
Edit: ALSO considering Noah and the prophesied end of Fishman Island needs to happen at some point, it makes sense that this coincides with Jinbe's dream (which is to liberate his people from oppression). Aka, this shouldn't really happen logically until the Final War. And what's above Fishman Island? Mariejois. And who's there? Im and the Gorosei. This is the biggest reason why we won't see this location to full effect until the end of the series, not next arc.