Kizaru has had the character development of a teapot
His friendship with Vegapunk was shallow and unconvincing
The tension when he came to Egghead was never there to begin with
His display of power was severely underwhelming - no powerful moves to show that he was a real match for Goofy
He danced for Nika in a flashback which was outright cringe
He had almost zero important interactions with the main pair of Egghead, Bonney and Kuma
He got pancake-diffed and stayed out due to emotional reasons - lazy excuse to make headway for the real arc villains, Gorosei
Kizaru's character was better off as a Marine lapdog, not giving two shits about environmental destruction and upholding his own lazy justice
While Gorosei were wreaking havoc on everything including Egghead he was crying his heart out for "killing" his friend, which as it turns out is what Vegapunk wanted from the very beginning
Frankly it's still better than what Kaido got, but nowhere near as nuanced as the relationships that Kuzan had, the conflicts he had with his mentor Garp, and even Issho showed more real depth back in Dressrosa when he clashed over justice with Sakazuki