so the plan kind of seems to be clear:
Season 2: Loguetown (1 episode), Reverse Mountain (1 episode), Whiskey Peak (1episode), Little Garden (1-1.5 episodes), Drum Island (1-1.5 episodes), Alabasta (3-4 episodes)
Season 3: Jaya (3-4 episodes), Skypiea (4-5 episodes)
Season 4: LRLL (1 episode), Water 7 (3 episodes), Enies Lobby/Post Enies Lobby (4 episodes)
Season 5: Thriller Bark (2-3 episodes), SA (3 episodes), Amazon Lily (2 episodes)
Season 6: Impel Down (3 episodes), Marineford/Post-War (4-5 episodes)
Don’t think it will continue post-ts but if a miracle happens, following are my guesses:
Season 7: Return to Sabaody (1 episode), FMI (4 episodes), Punk Hazard (3 episodes)
Season 8: Dressrosa (4-5 episodes), Zou (1 episode)
Season 9: WCI (4-5 episodes), Wano (4-5 episodes)
Season 10: Egghead (4 episodes), (assumedly) Elbaf (4-5 episodes)
From here onwards, it is completely assumption:
Season 11: Hachinosu (3 episodes), Burn-Scarred Man (1 episode), Lodestar Island/3-way Davy Back Fight (1-2 episodes), Laugh Tale (3-4 episodes)
Season 12: Marie Jois/Final War