I never said that Togashi's approach is better (i think it is, sure, but didn't write it, and it's just my taste) and i surely don't think it's flawless. I agree with a couple of your points too.
My point was that I don't think Oda is the best comparison for that matter. The sarcasm was just meant to lighten the tone, i don't feel like being too serious when discussing action shonen mangas.
While I still didn't change my mind about the fact that nobody in the latest arc of One Piece had the sole role of shouting "brother Katakuri!" I'll let it slide and look at the subject from a slightly different angle.
I personally don't oppose large amounts of characters taking part in the same arc, they help to establish how huge the scale of events is, and they help to ensure that the crowds in the arc are no nameless fodder, at least to other character in-universe. Just ask yourself what is more imposing? a crowd of same-y looking unnamed characters holding guns and swords, or a similar crowd but now everyone is unique looking and holding a different weapon/using different power.
That's what Togashi's doing now and that's what he did in the Chimera ants arc and to some extent the Election arc as well. Just by examining the group of villains in the Chimera ants arc, who are… well, the Chimera ants themselves, you'll notice how Togashi tried his best to differentiate between them, both design wise and personality wise, and above all, to sell their distinctiveness, he gave them different abilities. The problem here lies on how much panel-time Togashi tends to give them, which is definitely more than needed, actually doing more harm than good, unnecessarily elongating the arc and/or decrease the potential time used to develop important characters. Take Rammot, Leol, and Cheetu for example, they were nicely designed and written, and they even had some scuffles with the main characters, but in the end, they amounted to nothing, and on a normal occasion there would've been no issue with that, but Togashi made the manga focus too much on them you're left wondering after their anti-climactic death, that's it?
This seems to be what's happening in the current arc but multiplied ten folds with numerous of newly introduced characters. Furthermore, most of them wears generic suits, and don't even have powers (yet). In the end, this is something that rightfully deserves being concerned about. Still, the arc is just starting (lol) and I don't want to jump the gun about anything, maybe Togashi surprises us with how he handles these side characters this time around, hopefully.
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Leorio feels like Usopp, a relatively normal character surrounded by the prodigies that are Gon, Killua, and Kurapika. He might not get an arc centered around him, but he still needs to get a highlight every now then to prove he's worth being one of the main protagonists. This highlight doesn't always need to be a battle, but Leorio is severely lacking in that part which makes people want him to showcase it.