The anime in 2026 looks perfect, with 1:1 pacing and the 2-cour 13 episode schedule. I think this wasn't clearly stated but I assume that we've got 3 months of anime and 3 months of break on repeat? It sounds better than 6 months of anime and 6 months of break, but I'm not certain of that.
2026
Anyway, the first cour ends with chapter 1138 - The Harley. That seems like a perfect wrap up before a break. Franky seeing the mural and anime-onlys learning about the legend is the last thing we're getting. That alone is enough to feed the fandom for the break.
The second cour ends with chapter 1151. Freeing Loki plotline is already resolved, Knights kidnapped the kids, Gaban is gone, Imu possessed Gunko and turned Dorry and Brogy into demons. In 1151, the people in the Underworld feel Imu's Haki and get ready to fight, and we get to freeing Loki for real. That's also a great point to wrap up the cour, as it's right before the flashbacks start in 1152.
Flashback starts at the very end of 1152, so I would love if they went a liiiiittle bit over the 1:1 pacing but I'm not holding my breath hahaha.
2027
But going forward, 2027 is a bit worse when it comes to distribution of the chapters.
13 chapters later, in 1164, Xebec has been turned into a demon and his battle with Roger and Garp has started. 13 chapters later, in 1177, Imu defeats Usopp and Luffy with Loki reach Gunko-Imu (that's actually a great place to end the cour haha).
So I wonder - and I know I shouldn't get my hopes up on something nobody promised, but it would be much better if they boosted the pacing a bit in 2027. Loki flashback takes exactly 20 chapters (1152-1171), so putting all of that into 13 episodes is over 1.5:1 pacing and that's asking a lot, but it'd be a perfect outline of the third cour.
In that scenario, the fourth cour could very well be the last one, as Luffy and Loki join the fight against Imu's forces. So far, we're 10 chapters into the finale (11, if you count the spoilers), so that could end up close to 20 chapters again, or more. For comparison, Egghead had 68 chapters, and we're at 56 (57) chapters of Elbaph now, so it could end up similar.
More on the pacing
Egghead Anime sped up the pacing of the final 8 episodes to 1.5 and sometimes 2 to 1 pacing, so it can happen again. Obviously, I'm proposing something of a much bigger scale, 26 episodes, so I'm not really putting my money on it, but it's a fun topic to compare and speculate on.
Going with purely 1:1 pacing, Elbaph will conclude in 5 cours (unless there's some new development), but I see that 4-cour schedule would make more sense aesthetically, with all of Loki's flashback condensed into cour three. I'm sure Toei takes that into consideration now that they've went seasonal and they might not want to wrap up a season on an awkward chapter but... that's still nothing definitive.
Or maybe the 2027 episodes will go for 26 weeks straight with no breaks. That'd fix the problem with taking a break on an awkward episode without affecting the pacing. Gunko-Imu versus Luffy and Loki is a fine moment to wrap everything up.
All in all, it's all guesses for the future, but I find it cool to have some insight now that we have a very strict, definitive schedule. So that's the post. 2026 looks epic. 2027 looks... fine haha.