If you take it in terms of the overarching narrative some stuff could've been cut, but I feel that everything was in some way related to the main narrative, and if you take it in terms of the narrative of the book itself then no time is wasted. There's almost no fluff, no time spent with characters more than is necessary to show us something happening or some important character development.
[spoiler]In terms of how the book related to the main series narrative I think it was all quite important. The events in Harndon are all obviously relevant, with the stories relating to Pye's workshop, Jarsay, De Vraillys influence, the war of slander on the Queen, etc, all being done relatively succintly but setting up major narratives for the next book. Everything the Red Knight did was directly related to his efforts in Morea, which in turn are important as, at the end of the book, he is now the Duke of Thrake with control over the armies of a unified Morea, with the gratitude of the emperor and leverage over the princess, which will be of great help if he wishes to try and claim Alba and bring it into the empire which he has a massive amount of power and respect in, and these events also led to Harmodius obtaining a new body, and he will obviously end up being a major player on one side or the other. The Morean storyline also served to introduce and show us the relatively quick progression of Mortirmir, who will likely become an even more important character related to Gabriels story. Same with Kronmir; relevant first to the immediate story of the conflict between Gabriel and Andronicus, and perhaps will stay around as a character to assist him later. The events in the northwest with the Wild were all relevant, with various powers realigning in preparation for the coming war, with the stories of Bill, Nita, Ota, Tapio, and Thorn all being important to this narrative. De Marche and Hartmut in the north were important insofar as setting up the Gallish aggression in Nova Terra and the conflict that will arise there, and the very small amount of stuff in the Gallish court was important in setting up tensions within Galle and the possibility of civil war, or at the very least, incredibly strained relationships between the king and some of his more powerful subjects.
I really can't think of anything in this book which didn't achieve something important or wasted time, to be honest. In fact, in retrospect I feel it tried to be a little too concise where it could easily have used another 50-100 pages or so, to flesh out one or two characters and to show us the aftermath of the story. For example, I would have very much liked to know the specific directions that Kronmir and Mortirmir are going in, as well as what happens with the Emperor restored to power and between Gabriel and the Princess (considering the fact that he knows that she was one of the original betrayers), and exactly what status Gabriel has with being both the Megas Ducas, and also heading off to Alba with his own private company.
Edit: Talking of conciseness, there were a few things that stood out to me that made me realise how short this book was compared to what it could've been, or would've been in the hands of a worse author. For one, the incredible brevity of some of the small chapters relating to minor characters: when dealing with Clarissa, Kronmir, Andronicus/Aeskepiles, or that Morean riding officer in the wild, the sections would often barely be 2 or 3 pages, sometimes less than a page, just enough to tell us what we need to be told and no more. The second thing was noticing storylines and subplots that other authors probably would've spent so much more time fleshing out and wasting time on when no time needed to be wasted: Mortirmirs aethereal progression, minor romances between various characters, the personalities/development of some of the more minor characters who were only there for the window they provided us into events (ie, Clarissa), and so on. Sure, if I went through it I could find some more bits that we didn't need and that could've been cut by a page or two, but the amount of stuff that happens in this book would likely have taken at least several hundred more pages in the hands of many other authors.