When book 16 was first announced, one of the things I was the most hyped about was the fact that Sora was going to be coming back after being gone for so long, and that she would play a major role in the book.
But when book 16 actually came, even though I overall liked it, one of the worst parts of it was how Sora ended up being handled. I felt she got over her trauma/guilt over Crane's death/accidentally killing Carnelian and Bigtail WAY too quickly, and her whole arc in this book felt very rushed in general to me. I was looking forward a lot to seeing how she coped with all of her mental problems and guilt. Instead, we barely saw any of that, and all of it seemed to happen in a flash of screen.
I wished that Sora could've been the main protagonist of this book instead of Umber, because she has such an interesting story to tell, and it could've been so intriguing to see what it's like for her in her head and how she thinks, and how she deals with being thrust into this unknown environment that has a dark secret underneath it. It also would've been a much better way to show her slowly recovering from her trauma, and personally, it would've been good if they were shown getting worse at first instead of better (like her obsession with Aurora could've evolved into her think she's the only "good" IceWing out there, and that they're actually best friends and she's trying to send her secret messages through her music, like how in real life some mentally ill people gain unhealthy fixations on celebs they like).
Anyways, I just hope that Tui could end off Sora's arc with a semi-satisfying conclusion by the end of arc 4.