In the first place the concept of the Supernova was a marketing ploy that was forced on Oda by his editors to spice tings up a bit, so he's had to kinda somehow write them around his original ideas, so it's somewhat understandable that he hit a road block with what to do with them for the final stretch of the series. Prolly wanted to give them some sort last hurrah before taking them out of the PK race hence the rooftop flex and the Law/Kidd v Lilin fight. Still though I'd have rather he just leave Joker in as powerful ally for Kaido on Wano and just progressed Law's story organically with that and with that he could've made Joker as strong as he wanted and also given Law an opponent that he had a chance of beating with a bit of struggle. This would've have fit perfectly with his D plot line given Doffy is a tenryubitto and after that he could've just made Law accompany the SHs as an ally or Oden type "traveller" figure to help achieve his dream as let's face it Law has no chance uncovering the mystery of the Ds with just his current crew. Then with Kidd, he could've had him clash with Shanks off panel, maybe given us a Teach v Ace kinda 1 chapter encounter to have him organically fall to Shanks.
Fair enough on Zoro ^^. I'd argue he got a lot of good focus on Wano regardless but Oda instead of just fight focus, could've written the shit he gave us in the SBS about Zoro's family into the plot and given Zoro more plot focus. Maybe even made Orochi a strong character that was Kaido's strongest subordinate instead of King who was just a strong opponent.
Tbf to Oda though, if I consider the possibility that he might be rushing a bit to finish the story then, albeit controversial and unsatisfying he's been able to get easily get rid of one troublesome Yonko and thus doesn't need to write a separate story for Linlin falling and also been able to remove Law and Kidd from the story or rather more specifically the PK plot line whilst giving them some hype justifying the narrative written around them as promising captains of the new gen on Wano.