Really, I think my biggest complaint about Sacraments of Fire is the same one I have a lot about DRG's works that all but have the words 'part 1' on the cover or end with the words 'to be continued': It's a lot of set up. It's not bad set up, not unengaging, but by the end, it feels like we haven't had much chance for resolution. It only starts to feel like things are happening around the last few chapters, with the rest of the book spent maneuvering everyone into place.
That said, I do appreciate the way that he's portraying the Ascendants conflict. I was dreading that it would be straight up flashbacks, which I felt wouldn't give the story its proper due. Instead, we're getting modern day Kira (more or less) back in that time frame and seeing it from an alternate perspective, weaving it into the modern story. I still would have liked a solely Ascendants story set in the post-Soul Key time frame, but I consider this a good alternative.
Obviously, the conclusion is still to come, but I'm honestly excited for it in a way I haven't been for a while, mostly due to DS9's overall absence in the modern Trek stories. Now, with the biggest lingering plot thread about to be dealt with, we can see the DS9 story move forward. We're about to move beyond where there's a road map, and I'm eager for the chance (much like Sisko regarding the exploration mission for the Robinson).
I am, though, noticing the same trend that has fallen on the TNG novels, in that I have no idea who half of the people of importance on DS9 ARE anymore. Ro, Cenn, and Blackmer are the only characters who I've got a solid grasp on as characters. There are a handful of other characters who are spoken of as having prominence, but I still don't know who they are. And even some of the characters I do know and have cared about got little attention - Quark gets just a couple of appearances, Nog's a focus for about a chapter before leaving the story (narrative constraint, given his appearance in The Poisoned Chalice, but still), O'Brien has a brief appearance in the first chapter then disappears, Prynn's only appearance comes near the end for a reprimand for her actions in A Ceremony of Losses... The modern day DS9 crew are surrounded by characters that I have no concern for or connection to.
I'd just like to see a few more stand alone stories that let these characters GET developed, give the characters of focus location beyond a central select two or three have more of a chance to make an impact. It's what I've loved with the Voyager novels' slower pace, and I'd like to see more of a chance for the TNG and DS9 novels to get that opportunity.