I think I'm realizing why some are having a hard time feeling emotionally invested in Yamato. It's probably mainly due to how the emotions/moments she has had haven't really been used to connect to Luffy and the others. Like with this moment where she's hurt and doubting her abilities, instead of having Luffy look directly at her and reassure her that everything will turn out fine in defeating her warmongering dad, he instead looks away and simply tells her to help out Momo. It's definitely not like with Arlong Park where Luffy looks directly at Nami in her pleas for help. So yeah, more than just having characters experience emotion, it should also be about how that emotion is used to connect characters together, which may be yet to be seen in Yamato's case.