Oda can do what he wants.
But he still follows patterns when it comes to key elements of his storyline, and new crewmates are part of that pattern. He's only unpredictable when it comes to certain revelations, character introductions, and other things like those.
She doesn't have a bounth yet because she worked under a warlord. Its not fujitoras choice to not give her a bounty. Its the government that makes bounties. They most likely have Doflamingos whole crew on file and will send out her bounty after his status has been revoked
Admirals have the ability to make these things be overlooked. This is why the Franky Family didn't get bounties for their invasion of Enies Lobby.
This isn't even the only route Oda could take, but it isn't impossible.
If it can Robin it can happen again. Dressrosa is pretty much just like alabasta and almost everyone can agree on that.
Robin is the exception to the rule. While Dressrosa may have some parallels to Alabasta, it almost certainly is not a 100% mirror of the arc.
And if it was, Viola would've had a bigger presence, which she didn't.
This to me is more than what Robin did in Alabasta
Robin had a presence starting at Whiskey Peak, where she was introduced with a unique personality and design. She met the whole crew in that encounter too, and interacted with all of them.
Robin was present behind the scenes for the first half of Alabasta, and then had a bout with Pell. She then helped Luffy survive the aftermath of his first battle with Crocodile. She then watched Luffy's second battle with Crocodile and helped get information out of Cobra. After that, she took Cobra with her to the Tomb of the Kings, encountering Tashigi on the way and taking her out. At the Tomb of the Kings, she read the Ponyglyph and we got a glimpse into that aspect of her dream. Then, Crocodile came, she "betrayed" him, and he attacked her with his hook. And then, finally, she gave Luffy the antidote to Crocodile's poison, and was then saved by him against her will.
Is this really less than Viola's minimal screentime in her introduction arc?
Regaurding her adding to the cause she basically started this entire fight by sneaking luffy into the castle. She found laws keys and gave the strawhats a map to the factory.
Yeah, she did those things. And then she stood around for 40 chapters. Meanwhile, every other Straw Hat member stayed in action until the end of their respective arcs, and kept contributing to the cause.
Her confrontation with Doflamingo is, again, a nice character defining moment for her. It'll help resolve that part of her character quite nicely for the epilogue.
Her distinctive look is her lips to me the most. Her hair style is a bit different to most people and up until recently she had a rose in her hair.
If Oda can move Robin's hair and make her look very similar to Viola, then it's not really too unique.
She also wears a dress which no important female character in one piece has been shown in, let alone fighting in it.
Plenty of other characters in the series have worn dresses, with the most important ones on my mind right now being Nami and Vivi.
Her personality seems to be rather passionate and caring in a way.
This isn't really that unique. What's her quirk and unique personality trait that every other Straw Hat has? It's always something that makes them stand out from other individual side characters too.
Regarding her dream, it doesn't have to be stated yet. Brook, Robin, Nami, and Usopp revealed their dream after they initially joined.
We had an idea as to what their dreams were. Brook's past with Laboon and his promise was revealed in the middle of Thriller Bark. Robin is, again, the exception to that formula (and even then, we had a clue as to what her dream was with the ponyglph scene in the tomb of the kings). Nami's dream was hinted during the Buggy confrontation, and then actually emphasized and explained during the Arlong Arc. Usopp's dream to be brave was also revealed in his arc, way before he joined.
Meanwhile, Viola's only desire is for her family to be safe from Doflamingo's tyranny. What would a realistic dream for her even be, seeing as she's been fighting for her family's sake for the past ten years?
Almost forgot her powers. Luffy is the Captain and if he has a problem with it he'll just tell her not to spoil anything or if she warns them about anything he'll ignore it like he usually does.
Then what's even the point of her coming along, in your eyes? Luffy is never going to want the adventure spoiled in any way.