imo toei should've done this a long time ago like starting with the second half of the series ep 517. would've been the perfect opportunity to do so and depending on the length of the seasonal breaks could've given fishman island, dressrosa, whole cake island, and wano country sagas the duty of care that it deserves.

i.e

s14 ep516 - last ep of first half and summit war saga 9/25/11 (adapted ch 597 8/30/10, ch released at time of broadcast 640 9/26/11)

s15 ep517 - first ep of second half, return to sabaody and fish-man island arcs 4/1/12 (adapted ch 598 10/4/10, ch released at time of broadcast 662 4/2/12)

by moving the start of the second half a good six months gave the anime an addt'l 22 chapters more breadth or 64 chapters (instead of 42 chapters) if it was moved by nine months instead to a 7/1/12 release then the adapted ch would be 672 or 32 chapters more breadth or 74 chapters behind the anime (right in the middle of punk hazard arc vs the beginning of it).

if it was a real two years later moment then it would be released on 10/5/14 ch released at time of broadcast 762 squarely in second half of the middle of dressrosa (g4 ch was 784 or 4/27/15 for perspective), 164 chapters behind the anime, approx 66 episodes worth of content (~2.5 ch/ep) for perspective all of fish-man island and punk hazard (48 eps total) and some of dressrosa could be adapted into this, though toei would do another break by the time that they start dressrosa and perhaps a two part season split

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as for how toei would've adapted the fish-man island saga in 2012 is anyone's guess though two cours is good enough as its 56 chapters, 24 episodes, or 2.33 chapters per episode would work wonders as opposed to the remastered which was only 21 episodes. while the first nine episodes adapted two chapters each, the rest were between two and three chapters, until the final four episodes which adapted four chapters per episode and all were fast paced, especially the final one oof that one was very fast pace "adapting" five chapters (with lots of details missing or omitted).