@fuzi11:
Yeah, I don't need an entire arc dedicated to him after what we already got in Fishman Island and all the tidbits before and after.
We already learned of his past with Fisher Tiger, Arlong, the Royal Family and Otohime on Fishman island, as well as his connections to the World Government as Shichibukai. We learned about his past with Whitebeard and Ace during Impel Down and Marineford. We learned about his connections to Big Mom (it might be interesting to see how the connection with Big Mom was established, but we know enough to fill in the blanks) during Fishman and Whole Cake.
He apologized to Nami in the name of the entire Fishman race, and we got the forbidden blood transfusion with Luffy to cement their connection.
But most of that background is presented piecemeal, as exposition, or as secondary parts of a larger emotional narrative thats not really about Jinbe in particular. The scenes with Nami and the blood transfusion are nice, but Jinbe is kept out of focus for such a large part of the Fishman Island arc that their effect are blunted. As .Acess timeco. points out, it'd have seemed more fitting for Shirahoshi or even Fukaboshi to do the blood transfusion, given how much more prominent they were in the arcs emotional zenith.
–- Update From New Post Merge ---
@GetsugaZoro:
He accepted the invitation in Fishman Island, but said he had to solve something first, that was his arc where his joining story happened, he was as important as any SH in Fishman Island and the arc ended with him giving his blood to Luffy, he wasn't just a supporting cast like anyone else he was the main "supporting character", just like most SHs before they joined
The main supporting character of the Fishman Island arc was Shirahoshi, not Jinbe. He was not the emotional focus in any way.
@GetsugaZoro:
This joining was different, it was built like you said by various important moments he had with Luffy ever since Impel Down where they bonded, moments really important to the series that arguably might even make him closer to Luffy than some of the older SHs (I know that isn't measured, but I think we all know what I mean).
@MiyamotoMusashi:
Only that Jinbe was involved in the turning point of the story and served as the guy who pulled Luffy out of the darkness which had more significance than any kind of "specifically selling" a new nakama. That sold me on Jinbe already, everything else would only add to that to be honest.
Heres the thing: I agree that theres a ton of great moments featuring Jinbe, particularly at the end of the war. But almost all of those moments revolve around Luffy; how Jinbe saves Luffy, cheers Luffy up, or -routinely- how much Jinbe respects him. And thats cool and fine, all Straw Hats have those moments…But what about the moments about Jinbe alone, about his non-Luffy based wants, needs, and desires? Jinbe doesn't really have any equivalent to a Hiruluk/Bellemere/Saul/etc character relationship, nothing to compare to Brooks "Trio...duo...solo" moment, no defining moment that crystallizes his dreams down to a single instant like when Franky vovs to create the perfect ship as the sea train torpedoes him.
Jinbe is built on Zoro at Thriller Bark moments...but Zoro had more than that.