I really wish Oda hadn't drawn only on yokai for the gorosei monster forms and used something from 5 major cultures or some demons from the Ars Goetia. These guys are supposed to be the rulers of world, not just Wano and should sort of have a global monster theme or be monsters which are considered like demon kings to represent their authority.
Like Nasujuro as Orobas or maybe even a Nuckelavee would've been pretty badass too.
Or Warcury as a Babi Ngepet, etc etc