De-lurking for the moment to register an alternate reaction to the book. While any and perhaps all of the changes to the DS9 characters and universe have good potential, I found the scope of the "crisis" which triggered those changes underwhelming. The book itself acknowledges that once the fleet is rebuilt in a few years, it won't matter that the Typhon Pact has slipstream.* So making that the catalyst for dramatic changes felt to me bland -- this is what Kira's life is ending/being transformed over? This is what the wormhole is closing over? This is what Odo is racing against time and being stranded for? In addition, the big standoff in the wormhole didn't make sense. It's not like immediately upon arrival with the Dominion technology the TP could have started churning out slipstream ships. Why not cloak the Defiant, let the Romulans go through, follow them through the TP wormhole to the Tzenkethi station, then call in reinforcements and capture or destroy the station? (It was also exhausting for me to read a _third_ book where the TP acquiring slipstream is the focus of the action. It makes in-universe sense that they would keep trying, but as a plot device felt repetitive.)
Also, the missing five years were keenly felt. Wouldn't it have been great to see the Eav'oq or the Even Odds or Taranatar come to Odo's ship's rescue? What was Raiq and Kira's relationship, and what will happen to Raiq in Kira's absence? What was Sisko's last contact with the Prophets, and why didn't they tell him that he had completed his tasks, or why didn't he sense it?
Also, how can Sisko so easily leave Bajor? Just because he is disconnected from the Prophets and the wormhole should not eradicate the emotional and social ties he spent more than a decade building up. And as many have already noted, it doesn't make in-universe sense for Starfleet not to use slipstream to continue exploring the non-Dominion parts of the Gamma Quadrant (they sent a whole fleet to the Delta quadrant after all, where there was no official Federation contact, as opposed to many civilizations in the GQ where the Federation had officially opened relations). Whether Odo wants to return or not is a question worth exploring, but it is highly unlikely that he is "stranded" in the AQ.
In short, although the book was richly written, and the non-DS9 elements were by-and-large excellent, I couldn't help but feel that the series and characters were dragged along for a ride that they (or I) hadn't been properly prepared to take.
* I can't find the reference right now to check whether this statement was made even after it was known that the TP would have been able to equip all of their ships with the technology as opposed to the Federation's more limited deployment of slipstream. But (a) if the Typhon Pact can figure it out using Dominion technology, then certainly the Federation can do so, and there are all sorts of reasons in Odo/the Dominion's self-interest to give the necessary technology to the Federation and (b) where is the TP going to get all the benamite to power slipstream on all of their ships?