I take Yamato over Carrot anyday.
But yes, I do want her to join the crew. And I also do think that she has a couple of things going for her.
1. Yamato is gonna have to leave Wano after this arc, whether kaido falls or not. If Kaido falls, Yamato can join the crew anyway and leave Wano for good, but even if Kaido doesn't fall this arc, Yamato can't go back to his papa knowing her daughter betrayed him. She was already beaten and locked away by him before, after her betrayal kaido is only be more cruel towards her, and if he doesn't kill her he will certainly make sure to lock her away forever. Plus if kaido and the beast pirates fall (whether Kaido is killed or captured), the WG and Marines will go after Yamato like how they went after Ace anyway, so its best if she left with the straw hats.
2. Suppose Yamato does leave Wano, she most likely to join the straw hats than leave on her own. All her life she's probably grown up in Wano for as long as she can remember. she won't be able to go solo and explore the world all be herself, she most likely has zero experience in navigation and sailing.
3. Yamato ain't weak or useless and can actually fight. She was able to take down Ulti in one hit, right now id rank her above the mid trio. This is good news because it shows that Oda will be able to give her 1v1 fights in the future like he does for the monster trio, unlike poor robin. Carrot couldn't beat Daifuku and Nami is always given powerful buffs like Zeus and climatact to one shot fodders, its a problem that Carrot, Nami, Robin all share, they are just fodder sweepers now. Yamato is at least strong enough for Oda to give her 1v1 fights.
4. Luffy is the first person that Yamato met, just a check off that happened with every other straw hat that joined before.
5. She has a sad backstory, child abuse. Was constantly beaten up by her papa as a kid. Much sadder than Carrot losing Pedro.
6. She's a girl, and a hot one at that. With jinbe already joining, another girl like Yamato is needed so the crew doesn't become such a sausage fest. And yes, compared to Carrot, Yamato is hotter, at least she doesn't look like Chopper.
7. Her connection with Ace may also be a reason. We haven't seen her full backstory yet, but i've just read the official Viz Translation and yes Yamato does indeed ask Luffy to join his crew, its not a mistranslation. She literally says and i quote: "So speaking as Oden Kozuki, I've followed the proper logic that says, as Ace's brother, you should be giving me a ride on your ship" Source here:
https://www.viz.com/shonenjump/one-piece-chapter-985/chapter/20882?action=read
Mind you, the same thing also happened with Tama, Tama/Oden/Yamato all asked to be able to join pirate crews, Oden was the first to succeed by joining Whitebeard's crew, and I believe that Yamato will be the second by joining Luffy's crew. I'm not counting Izo since he hitched on the ride by accident. Tama also asked to join Ace's crew and likely Yamato did the same, but they were both probably too young at the time. Now Yamato is grown up and she wants to get her chance to explore the world, just like how Oden was able to.
8. I don't buy the 'weak dream' argument, its no weaker than 'Carrot should join because Pedro died', also what about ussop and he's 'to become a brave warrior of the sea?'
9. Design, some people say she isn't unique enough. I disagree. She's a melee fighter unlike Nami and robin. She looks taller than both of them. She has horns.
10. Role in the crew, doesn't have one yet but im sure Oda can just make one up. i mean for the record a 'sniper' like Ussop isn't mandatory in a pirate crew either, he still joined. Carrot was easily given the reason to join so she can be a lookout, Yamato can fulfill that same role just the same. She's tall, and just like Carrot she hasn't seen much of the outside world, i'd think her being the lookout would be pretty easy and come very naturally for her. We also haven't seem what Yamato is good at other than her strength, so its too early to say, maybe she has a talent honed after being locked away for so long, sneaking and lock picking maybe?
Edit: I'm just gonna edit this one in as people have bought up this new issue they have with Yamato that I didn't see before and that it is the argument that we are too far into the arc for Yamato to be developed enough to be a Straw Hat. Again I disagree, Yamato can be further developed even after she joins the crew. It happened with Robin, Oda could easily do it the same for Yamato.
#YamatoforStrawHat