So I’m going to be honest, I don’t like Yamato as a character. She seems like a very fanservice-y character. Someone Oda honestly might have inserted last minute on an editor’s request to possibly gain traction with the fandom, such as the supernova.
Nonetheless, I believe she has a decent chance of becoming straw hat. Why?
She knows Luffy’s dream. This isn’t something just any character is given knowledge of. No only a select group of characters who are intimately close to Luffy know his dream.
the only people who know it are Luffy’s brothers, Shanks, the SHs,… and Yamato.
Still I feel like as a character, Yamato just doesn’t fit with the SHs. Maybe Oda can change that, but until he does, I feel like she’d honestly make a better addition to the grand fleet or even Law’s crew, than the SHs.
Nonetheless, I believe she has a decent chance of becoming straw hat. Why?

She knows Luffy’s dream. This isn’t something just any character is given knowledge of. No only a select group of characters who are intimately close to Luffy know his dream.

the only people who know it are Luffy’s brothers, Shanks, the SHs,… and Yamato.
Still I feel like as a character, Yamato just doesn’t fit with the SHs. Maybe Oda can change that, but until he does, I feel like she’d honestly make a better addition to the grand fleet or even Law’s crew, than the SHs.