Did you really think so?
Ever since 6.2 I few like the characters have been all out of character for a long time now.
The main thing I notice is that either the writer reduced the character to one single trait at a time, or they just speak like "the Scion" described by OP.
Zero during her story, although she seems less annoying than Wuk Lamat, does the hat thing repeatedly, just like WL talks about peace. They both are one-note characters that barely learn anything and keep repeating the same mistakes and questions and acting the same way.
Y'shtola, the writer knows she is supposed to be smart. He seems to struggle writing characters actually being smart, so every solution she presented during the whole story were things she did offscreen. She talked to Cid offscreen and then already had the device we needed to take to the First. She talked to G'raha offscreen and got instructions on how to use the tower...
In 6.55, G'raha for some reason is saying "hear, feel think", like it randomly happens during Dawntrail as well. Him offering to stay behind so Krile could go is completely out of character as well, because didn't we just promise to take him to a new adventure? Didn't he always get excited to go somewhere new?
If only the game had given us a reason of why it's so important for him to stay and take care of things, then it wouldn't feel so bad. But in Dawntrail, we only got him saying "I took care of the most pressing matters". What pressing matters? What was so important that G'RAHA TIA didn't flinch at the thought of not going on an adventure with the Warrior of Light?!
Krile didn't act any less different than she does during the whole DT MSQ. It's been a while since she last teased someone or acted with more conviction than calmy saying "I want to learn about my past".
The twins...appear out of nowhere and say nothing.
The one that seemed to have personality in 6.55 was Wuk Lamat. And it felt fresh and fun because we didn't know her yet, so the idea was that "oh ok there's more to find out about her! She is cheerful and extroverted, but seems very naive as well." and...we saw the exact same thing during the MSQ. Even worse because of the peace and smiles repeated dialogue.
The one thing 6.55 did better was Wuk Lamat and Erenville talking while they were eating, which wasn't very long but it was cute. And we could've had more of their friendship in Dawntrail, but considering how much time we spend with them, they barely talk. Sometimes it felt like they didn't even know eachother well...
The same writing problems of Dawntrail were starting to show as early as 6.2 for me. Maybe we didn't notice them as much because they were shorter stories, or we were expecting less because they were "just patches", hoping the expansion would be better...but they were there.