I don't think there's much character development going on in Arya and Dany's AffC/DwD plots. World building, absolutely, every page has that and GRRM is brilliant doing it. But Arya and Dany have mostly been spinning their wheels for a while now. I'm not necessarily saying that's the worst thing, since we get world building out of it, but it seems clear to me that they're two pieces of the jigsaw puzzle that GRRM had to simply put off to the side while the real meat of the story is happening in Westeros or with other characters like Barristan and Tyrion.
Er, I don't think you remember Arya and Dany's stories in the books well then.
Daenerys' last chapter has her embracing her Targaryen heritage. Fire and blood. Dragons do not plant trees. Hell, she disowns the Meereenese as her children and says she cannot make a people good realizing she belongs in Westeros. She's meant to conquer and brute force people into doing what she want not to compromise according to her. In fact that's why her whole ADWD story was her being put in more and more situations giving up things for peace. She hated every second of it and then she snaps at the end. No more compromising.
Arya on the other hand has been progressing into Dexter. Her last chapter has her enjoy killing so much that the way she's talking about a mark of hers is framed as if she were talking about someone she wanted to bone. "She wanted him so bad." It's kinda sad.
Show Arya never gave up her soul. Book Arya has been killing people she doesn't know because the FM told her to whilst killing people she's had on her list and getting a sort of ecstasy out of it.
Cat and Arya have a lot in common actually.