Then why even set up the first interaction to begin with if it couldn't be seen through until later on?
-he had set up Marco vs Big Mom and Perospero already and needed something to stop that
-he wanted to show Carrot’s Su Long again, and Wanda’s for the first time, and since it seems Su Long will play no other part in Wano, it had to happen then
-he was putting all the other Minks on the roof so he needed to show why Carrot and Wanda weren’t with them
This also disregards the words said to Carrot. Perospero told Carrot that she's not fit to deal with pirates and essentially that she should've just stayed on Zou. As enjoyable as he is, he's still the "baddie" and Carrot is the "goodie". His statement is just begging to be subverted at some point. In other words, Carrot will make it very clear that although she did totally underestimate what she was in for, she is still fit to keep moving forward like Pedro told her and face pirates out on the seas.
No, disregarding it would be if it ended there, Carrot stayed on the ground, nothing else happened. There will be a conclusion to Carrot vs Perospero where Perospero gets whats coming to him.
But since Oda has spent a grand total of five pages (and a solitary panel) on Carrot in the 28 chapters since she went after Perospero, with huge chunks of time where he didn’t bother even cutting to it to get a catchup of how Carrot is doing, I don’t expect it to get the focus that Carrot going SunLong the first time did got.
How does that work for the climax of her arc? How does the biggest and most significant moment happen in the middle? How is the climatic resolution inferior to the build up?
Can you name another instance in the story like this. Where the resolution of a character's arc was not the most impactful, significant moment for them?
Resolution and climax are not the same thing. A climax is the highest point of drama, regardless of when it falls. A resolution is the end.
Robin’s I want to live was far more memorable and impactful than her actually beating Spandam at the end of the arc, or thanking the crew for rescuing her.
Wyper killing Enel was his standout moment, more than knocking down the Giant Jack or seeing the party of both Skypiean and Shandoran.
The resolution of Kyros and Rebecca’s story wasn’t them beating Diamente, it was them deciding to live together in peace.
The biggest example in fiction I can think if is the resolution of Frodo’s story being to leave the Shire, but the climax being his decision to keep the Ring and him and Gollum struggling in Mount Doom.
With the way Carrot’s story has went since, I very much doubt beating Perospero will match the impact that her first Su Long transformation had. Carrot’s Su Long was the first time we’d seen it from any Mink, the sacrifice of Pedro was fresh in the memory, it was only five people against an entire fleet, there was only three plotlines of note to be focused on (Sunny escapes, Luffy vs Katakuri, Sanji and the cake).
Here
-Pedro died ages ago and it’s not especially relevant to the arc as a whole, which is all about avenging Oden and freeing Wano. Carrot and Perospero (and Big Mom) very much feel like interlopers who are only here to get the plotline solved quickly
-it’s not especially high stakes. On WCI it was the Strawhats surronded, if Carrot hadn’t turned Su Long they might not have escaped. Here, if Carrot doesn’t beat Perospero, it’s no biggie, there’s tonnes of other powerful fighters that can do it
-rather than the three broad plotlines of the escape of WCI, here Carrot vs Perospero is only one plotline- with barely any focus and the least to do with the purpose of the arc- competing with two fights with a Yonko, three fights with a Calamity, two fights between the Worst Gen, five fights against the Flying Six, the fights against the Kurozumi clan. And that’s just taking a broad outline of the plots, it can be zoomed further in (what will each Scabbard do, what will Momo do, what is Hiyori up to, what will Marco do, what about Yamato, CP-0, etc etc).