Don't necessarily disagree with the rest but this is a massive overstatement/ underselling of Law's role. The narrative is clear. Law literally started this.
He did have a big role in starting the war, can't argue with that.
But the thing is, he did it for a reason- to end Doflamingo. And that reason is done. And since then, I don't think it's any surprise that Law hasn't been anywhere near important or prominent as he was back in the Punk Hazard/Dressrosa days
what we do know is that he's pretty much been the face of this whole Kaidou saga.
See, while you think I've been underselling Law's role, I saw this is overselling it.
He was the face, if you want to put it that way, of Punk Hazard and Dressrosa. Since then, he's been totally overshadowed by the Red Scabbard plot line. He barely did anything on Zou, just sort of... sat back and let Luffy enter him into an alliance with the Scabbards. Neither were in WCI, but the Scabbards at least had Pedro vaguely representing them with his talk about the Dawn. And on Wano itself all he's really done is have an ongoing fight with Hawkins and get pissed at the Strawhats, while all the other plots revolve around Oden's legacy.
You're downplaying the whole Kamizou smile situation. To put things into perspective, imagine if that was Zoro instead of Killer, that would arguably be the biggest, most emotionally taxing event to happen in Luffy's career aside from Ace's death. You also have Apoo one of Kaidou's underlings doing double agent work, bringing him to their base.
I'm downplaying it because Oda's gave me hardly any reason to care. Killer is the Zoro to Luffy's Kid, but Oda's barely shown them interact. Their fight with Kaido was offpanelled. We haven't seen any of their history together. The tragedy of Killer being forced to laugh means nothing to me, because Oda never showed us any of his past, he just has Kid tell us about it. Kid and Killer are a glorified Bellamy and Sarquiss with how little they've done so far.
This lack of attention he's given Kid, compared to the bonanza Oden flashback, just leaves his grudge feeling weak and hollow. Hell, we don't even know what happened to his crew, do we? Cause Oda hasn't bothered to tell us, we don't even know if it's important or not.
Funny you should mention Apoo though, cause I actually am more invested in seeing Kid fight him. It's not much, but at least from Saobody, to Punk Hazard, to the betrayal, we've seen that the two really don't like each other. If anyone's going to fight Apoo, Kid's got first dibs there. Whereas with Kaido, eh, he's in the line, but he's nowhere near the front.
Even if the writing around it lacks the slow buildup, Kidd has even greater reasons than Luffy to target Kaidou. Luffy's beef is hardly as direct.
Not really. Sure, Luffy isn't as close to Momo as Kid is to Killer, but when it comes to Kaido's vast list of crimes, forcing Killer to SMILE all the time is pretty low down compared to murdering Momo's parents. Never mind the vast list of crimes Luffy's seen Kaido's men commit since Punk Hazard. Luffy's schtick, that he got from Shanks in chapter one, has always been "beat the shit out of people who upset my friends." And Kaido's been responsible for way more crimes against Luffy's friends than he has to Kid.