@MrPecans:
It's not a big enough point to go back and forth on but I just think that a master like Oda could easily still add layers to her personality if he chose. I find her more visually interesting than the East Blue crew (minus Usopp) and personality/quirk wise, I think she stands on par with "Can I see your panties?" Im a huge Robin and Nami fan, btw. I only meant to compare early Robin to current Carrot in a superficial way.
I'd like to reiterate that more than anything I'd rather see no one else join the main crew. Carrot is a gun-to-my-head nakama choice.
But we got a whole lot out of Brook in literally the first chapter he was introduced. We got his unique skeleton afro victorian suit and top hat with dancing cane design. We had the "can I see your panties" joke. We had the skull joke puns. We got his musician profession, which Luffy wanted for years. We had the gag about him being an ironically rude gentleman. We also had his jovial personality and the sad overtone of it being a result of decades of isolation that made him desperately desire company, which already gives him depth. And that laugh. Oda had the willpower to restrain himself from using the most cliche pirate laugh ever for so many years just for this skeleton afro guy, and boy was it freaking worth it. Brook was a freaking masterpiece in his introduction chapter and I still feel second-hand shame whenever I am reminded of how people decried him as a potential crewmate despite accepting Luffy's invitation to join, even if he got ahead of himself and left shortly after.
I don't even find Carrot to look more interesting than anybody from East Blue besides Nami. And she still gets a free pass because she stood out by being the first "beautiful" female of her kind in the series. Zoro's got three earrings on one ear, green hair, three katanas, a bandana that makes him stand apart from other fictional swordsmen, and a samurai overtone with the haramaki. Usopp is unique with his overalls, goggles, army colored bandana, the Pinocchio nose aesthetic, and a slingshot for a long-ranged weapon in a pirate series instead of a gun. Sanji has suave gentleman attire, slick hair with one eye covered, curly eyebrows, smokes cigarettes, and a kickboxing fighting style. If I never saw One Piece and you showed me any of those three guys, I would have at least some sort of curiosity rise within me as to what series they are from because they would stand out amongst a lot of human action-adventure shonen characters in how creatively quirky they look, let alone act. They stand out from all of the generic plain faced, ridiculous spiky hair, and bishonen handsome protagonists. Just because they are human does not mean they don't have details that stand out from the crowd.
Carrot though? Out of context from the series, she looks like she could be from any series that stars anthropomorphic characters. Nothing about her looks distinctive enough from those types of characters, not one single detail. Because she looks generic, I would hardly ever be intrigued as to what series she might be from if I was not a One Piece fan. My only impression would be "oh, it's some generic anthro anime character". The hair, the attire, the anatomy, nothing stands out about Carrot besides maybe that cape she wore back on Zou.
Chopper is an anthropomorphic character too, but there are so many details about him that stand out in his design like the top hat, the blue Rudolph-inspired nose, one his horns being attached, the small cute mascot look of his hybrid form rather than looking like a tall mundane anthro character from the likes of the Regular Show or Bojack Horseman (thank God that Oda scrapped his original concept art idea for Chopper), and the fact that he has seven different transformations.
Personality-wise, maybe you kind of have a point there. But Nami and Robin still stood out with the former being a greedy thief who hated pirates and and the latter being coy and mysterious while having no trouble talking about assassinations or asking Luffy to join the crew. Carrot has nothing to her that doesn't already belong to another character. Goofy, gluttonous, and easy to excite into combat? Luffy. Naive kid who wants to see the world whose role model blew up suicidally? Chopper. Inferior swordsmanship while training to become a warrior? Zoro. She's into carrots? Sanji's already into all kinds of food (then again, Nami's obsessed with tangerines so this point is unfair). Hell, even the pretty art gag is a little bit redundant because a lot of people overlook that Usopp is already a great illustrator since he made the Straw Hat pirate flag and has references to drawing in color spreads and SBS sections sometimes.
I understand being adverse to an eleventh crewmate this late in the game (if they join after Wano Country, that would admittingly feel a bit too late for my taste). But I don't think any character we already know about deserves to join the crew. When we see the eleventh crewmate for the first time in full view, we'll probably know they're the one by how much they stand out both design-wise and plot-wise.