I think the reason why I don't care for reading an Azriel book, is because he feels like a "settled" character. To me, he isn't positioned to gain anything profound or substantial (other than love) because he already has things that characters normally gain when they go on their character journeys.
I'll use ACOSF as an example. Maybe unpopular opinion but I see that book as Nesta's story instead of Nesta and Cassian's story because I didn't learn anything new about Cassian or see further character development. Instead, his focus throughout the story is on Nesta and the impeding threats surrounding Prythian. I don't see him recovering from a traumatic event because the story doesn't show us an event he's traumatized from. If he is traumatized, it's from the past and off screen. I honestly don't know if it has bearing on his present (correct me if I'm wrong, i don't remember much). He doesn't need to learn about his powers, he already knows what they are. He's honed his combat skills over the centuries. He knows his history, his purpose, his role, his sense of self. He has established dynamics with his found family, he doesn't need to search for a new one. He has a home and a sense of freedom. He had all of these things when we met him. Is there anything else to see from Cassian as his own character? I'm sure there is, but I don't think we got that far yet. It's similar with Azriel. He has his issues with Mor, his thing with Gwyn, dealing with feelings of insecurity and inadequacy. But what else of him? He has some growing to do yes, but he seems tethered and grounded in so many other ways.
I personally want to read about someone who is untethered in a plethora of ways. Someone who isn't settled, who isn't "rooted" in place yet. The Archeron sisters are a given. Their stories involve learning about their new bodies and powers, understanding their sense of self and purpose, dealing with their recent and past trauma, finding a home and a family in Prythian, and so forth. And then...I think about Lucien Vanserra who is practically the poster boy for "untethered". He has so many unfinished stories left in him. He lost his home in Autumn and Spring, he sort of has one in Night but then he's also living in the human lands, so where is his true home? Beron wants to take over Prythian, will he be sucked back into the court that caused him pain and suffering? The man he thought was his father isn't, how will he deal with that? Does he need to learn more about his Day Court powers? What will he do to help Vassa and her curse? Will he ever reconcile with his brothers and mother? Will he ever reconcile with Tamlin? What's his dynamic with the Band of Exiles like? They're a pretty new friendship group after all. And this isn't even touching on his bond with Elain or his past with Jesminda!
This isn't about hitting rock bottom or who's better than who. To me Azriel doesn't have the meat to carry a story or journey I would enjoy reading about (emphasis on "I" because it might work for others though). So yes, I'm rooting for Elucien to get the next book as I think that book will be really dynamic.













