I think the remaining arcs will go something like:
Egghead (20-25 chapters) -> Fullalead/Beehive (10-15 chapters) -> Elbaf (30-40 chapters) -> Lodestar (50-60 chapters) -> Laugh Tale (<5 chapters) -> Epilogue
Very rough overview of how I think things will play out:
Egghead (20-25 chapters) -> Fullalead/Beehive (10-15 chapters) -> Elbaf (30-40 chapters) -> Lodestar (50-60 chapters) -> Laugh Tale (<5 chapters) -> Epilogue
Very rough overview of how I think things will play out:
- Short-ish Egghead arc that has the crew fighting/not fighting Vegapunk. A good amount of time is spent on loredumps and a couple chapters spent on Franky learning from Vegapunk. While there, the crew runs into Smoker/Tashigi/Sword. They form an alliance to save Koby together
- Short Fullalead arc where the Strawhats + Sword come into conflict with Blackbeard. Something goes awry that causes both parties to leave. No longer than 10-15 chapters.
- Crew goes to Elbaf after discovering some key piece of information that sends them there (Either Poneglyph or Vivi stuff). Fairly meaty arc with Shanks and/or Imu. Good amount of Usopp focus. All remaining major parties set course for Lodestar.
- Lodestar arc is a three way war between Blackbeard + Cross Guild + allies, Luffy + allies + Sword, and Imu + CP0 + Marines. All ancient weapons appear. Both Blackbeard and Imu are defeated. Maybe 50 chapters cause very little time is going to be spent on the island's locals
- With all four Poneglyphs and all major threats defeated, the crew arrives at Laugh Tale. They find the One Piece and the truth of the Void Century (Which will probably be funny/goofy instead of anything serious and epic). At most 5 chapters long
- Epilogue detailing what the crew gets up to and how the world was affected by the Strawhat's journey. No idea how long this will be, but regardless it'll get lots of content (Light-novels, anime specials, maybe even spinoff one-shots) elaborating on different characters/places after the manga is finished
I know Oda said he wants to finish it in 3 years, but it's likely that he's thinking in terms of pre-timeskip pacing. The Marineford Saga had 5 arcs (Sabaody, Amazon Lily, Impel Down, Marineford, and Post-War) and it only took 2 years to draw. He probably thinks he can do the same thing with the final saga. And honestly it should be pretty manageable if he focuses on the main story and only includes subplots that tie in with major characters (Franky/Vegapunk stuff, Zoro fighting Mihawk, Usopp meeting his dad, etc).
