This is actually great writing, too, since Izo finally got revenge on the World Government in the most satisfying way possible for killing his brother and father: Izo directly aided the advent of Joy Boy, the World Government's greatest enemy. The WG killed Ace to try to destroy Roger's Will, but, through Izo's sacrifice, Luffy was able to finally fulfil that Will and become Joy Boy.
I want ZKK more than anyone, and I wish people would appreciate some of Oda's great writing in Wano, rather than just complain about their headcanon not happening. Sanji didn't need to beat a Sweet Commander for Whole Cake to be good, and Zoro doesn't need to kill Kaido for Wano to be good.
Honestly, it pisses me off that Izo's accomplishment is being swept aside in the plot. Kiku's brother literally helped herald in Joy Boy. Izo died to bring about the Dawn. That's special, GIVE HIM CREDIT DAMN IT (hope I'm just complaining and Oda surprises us)
