Don't get me wrong, I love Katherine Addison in general. I love a good novel that comes from the realm of fanfic (hello, Winter's Orbit!). I love mysteries and a Sherlock pastiche. I love gender stuff! With all of that, I enjoyed the writing itself, but the book tried to do too much structurally and it didn't come together for me.
The Angel of the Crows is a Sherlock story, but the setup here is that Crow (Sherlock) is an angel and Doyle (Watson) took an injury in Afghanistan from a fallen angel that left them partially a hell hound (in a werewolf sort of way). Crow here is awkward but also kind, and so the relationship between Crow and Doyle where they each help and care for each other in their own way works for me. (I personally am alienated by "jerk Sherlock" and don't quite understand why anybody would ever like him.)
This book is also a direct retelling of a Study in Scarlet, the Sign of Four, part of the Adventure of the Yellow Face, and Hound of the Baskervilles. My Sherlock knowledge is not the best, and so it's possible there's other references I missed too.
For me, these Sherlock stories hewed too close to the source material. It's not that there aren't minor shifts around in the story to accommodate for the more supernatural elements in the world or of Crow and Doyle, but it's not quite enough to make a compelling story for me. When I already know what the Barrymores are up to in the Baskerville estate or about the treasure in the Sign of Four, I need something more: either something much more unexpected to happen, or for it to stretch the worldbuilding, or for it to highlight character dynamics in some fresh way. It just wasn't enough change in most of these cases to feel like all this merited a novel-length retelling with so many of the same details.
(I will say that the most fun twist was the nicely foreshadowed subversion of Mary Morstan at the end of the Sign of Four.)
The worldbuilding is a bit wild: airships, vampires, werewolves, ghosts, clairvoyance, angels, but also at the same time (somehow?)! a largely unchanged Victorian England. I have so many questions about "alternate history with magic" style changes where the magic and supernatural elements haven't deeply transformed society. There's also no indication of when or where all these things started existing or being possible; just that they're there and are largely accepted parts of society.
I was hoping that the reveal of worldbuilding was leading up to something like a supernatural mystery, or a case that more closely involved Crow and the angel consensus, or something with the vampire Moriarty plot, or even something to reveal deeper information about what angels actually are. In the end, we get a moment of connection between Crow and Doyle, but unsatisfyingly are left with nothing to tie together any of the disparate Sherlock stories, the supernatural worldbuilding, or the many loose plot threads.