Kaido originally had a longer, more Asian looking Hybrid, IMO, compared to the bulkier, more Western Dragon Hybrid we ended up with:
Oda likes using designs he had to scrap and saving them for the future.
Momo having a slimmer Hybrid would also help differentiate his Sword Skills compared to Oden's and others. Finally, Momo is a somewhat evasive/cowardly fighter, so having a form that's thinner/built for evasion is good for him.
This is why we haven't see Momo's Hybrid yet: Oda's saving it for a big moment, probably Pluton, Laugh Tale, or Final War related.
Oda likes using designs he had to scrap and saving them for the future.
Momo having a slimmer Hybrid would also help differentiate his Sword Skills compared to Oden's and others. Finally, Momo is a somewhat evasive/cowardly fighter, so having a form that's thinner/built for evasion is good for him.
This is why we haven't see Momo's Hybrid yet: Oda's saving it for a big moment, probably Pluton, Laugh Tale, or Final War related.