I doubt that Rooftop Piece wasn't a part of Wano arc - Oda is too prepared not to include that in advance, and his story structure is very flexible - but it definitely did feel disjointed from the very beginning, like maybe it was supposed to happen in different sequences later.
Like maybe Luffy vs. Kaido and Law + Kidd vs. BM separately, then the three SN vs. two Yonko end up on the rooftop to tag team.
Then Zoro beats King and Killer beats Hawkins and they go up to join their captains on the rooftop with Zoro already knowing ACoC.
It would make more sense as to how Zoro could scar Kaido with his ACoC slash instead of randomly using it out of nowhere + all that Enma wank