She is interesting. With what little we have of her, she's certainly made a strong first impression. To go through your points
1. Ace. I find this a strong, strong point in her favour. Ace's death is the turning point in One Piece, something that has unified all the Strawhats. It provides a link between them all. Yes, I'm aware of the argument that there are events that other Strawhats have missed out and that hasn't been a problem. But Ace's death transcends everything we have had in the series in importance. I think having every Strawhat share an understanding of what that meant to their captain would be a good thing.
2. Her dream. Going on an adventure is a weak argument. Simply adventuring is something every single Strawhat does. It's what every single pirate in the series does. A Strawhat dream needs to have one, climatic moment where they actually achieve this dream. How does "adventuring" fit into that? Every arc starts with the chapter "Adventure on X." Would Yamato not simply have fulfilled her dream by the very next arc then?
What would work would be if, like Jinbei and freeing Fishman Island, opening Wano's borders is not as simple as beating Kaido. And then Yamato actually needs to go with Luffy to fully achieve that. Would be a bit derivative after Jinbei, but Nami and Franky's dreams cross over a bit, so it wouldn't be that bad.
3. Role in the crew. Don't really buy Chronicler for her. She's simply missed too much to record enough of the Strawhats adventures. Don't really see a role sticking out for her unless Oda gives us a surprise twenty something year old cabin girl, which would be odd.
For other points
Her design is okay. She'd stand out in Strawhat group shots by pure virtue of her height. Unique fighting style, that's good. Potential DF? Will be interesting to see what colour her hair actually is. Personality wise, wee bit early to judge, and I don't really see that as a good thing. In general I think as a character she's not had as strong an introduction as, say, Ulti- not that Ulti is joining the crew. If Yamato keeps the mask that would actually help her stand out more.
She doesn't have a strong enough relationship with Oden. That's just a huge argument against her. Every other Strawhat has had a strong relationship with their inspiration figures. Yamato doesn't. There would need to be a lot, lot more in her flashbacks, and probably another character entirely to fill the Shanks/Kuina/Bellemere role. Luckily, a child needs two parents, so the big mystery of "who's the mummy" could answer that.
Tragic backstory, well, that'll probably come whether or not she joins the crew, can't imagine it was great fun being raised in the Genocide Pirates.
Overall, 65/35 on her not joining the crew. But Oda could still easily spend the next ten chapters giving her really heavy focus and dismantling every one of my arguments. So she's at least worth talking, and provides a breath of fresh air to what has been a very, very tired argument (Jinbei will die! Look, Carrot is in a panel with a Strawhat!)