@Shift:
Do as you wish, but there are legitimate issues in her way: not mature enough, no kunoichi skills to speak of, fruit power not conducive to shonen battles, etc.
She seems quite mature for her age, even more so than Momo. And maturing through the story is some great character development, so i don't see that as a negative point.
People in Wano have no understanding of what it means to be a pirate or a marine. Instead people dream of being a great ninja/kunoichi or samurai, but it basically mean the same thing, to be a great man/woman and achieve stuff. Her dream of being a great kunoichi travelling the seas is sort of equivalent of Usopp being a great warrior of the seas.
As for her power, it works. in RPG terms she is a beastmaster/summoner kind of class, she is basically the pokemon trainer of one piece.
Perfect ability for a a physical weak kid, she could tame new animals in every arc to protect her and provide with useful abilities.
Its not that new really, we have seen in almost every arc how animals fight alongside Luffy in a way or two, so we know Oda likes and uses the idea already.
But the most important points to look at is: her introduction and relationship with Luffy, connection and promise to Ace, dream, being sort of an outcast and low class, her possible group dynamic and role in the crew, which all seem very pro strawhats for now.
Her having purple hair, being the little sister of the crew, and having a unique first letter of her name also fits very well.
I can even see her taming the Godzilla of one piece and go toe to toe against Sanjuan Wolf! haha
We will see during the arc how her development and the story progress, but for now im all pro Tama, but i also recognize she could also just be a homage to Odas own daughters and their dog.