Oda literal made a SBS where he said he hates what they done to shiki, but acknowledge he cant change it now because there is too much material now
why would he reintroduce someone he said this about? lol. He is in the realm of toei fuckery
I thought Shiki showing up wasn't that likely, until his face was used by Higurashi in Wano, and then he showed up in the God Valley flashback.
Oda could just... not give Shiki the Float Fruit in the Manga.
Shiki's 20 year plan would be happening right about now.
Still hoping Uta shows up as a serious character at some point, too.