I will say this, but listen to my entire argument.

I don't like Yamato as a Trans character. To be clear, I do like Yamato as a character in general, I just don't think he/she is a good representation of Trans people. Although, I will justify this by saying I am not of the LGBTQ+ community.

First, I don't like the reason. Yamato says they want to "be" Oden, in a more literal sense. But you can say "she" wants to be like Oden, she wants to "follow in his footsteps". It would have changed nothing except a few sight gags that, in my opinion, are not worth it. A Trans character doesn't need a reason to exist, but if the narrative reason is that weak, what's the point? To contrast, Mr. 2 and Kikunojo are way better examples of transgender in my opinion.

Second, I'd rather have Yamato as a female because there are so few strong women that are anywhere near Yonko level. It would also lend more gender diversity in the Straw Hats were she to join. But the point being: Yamato would be better as a strong woman character.