Got my copy of PoN last Saturday. So far, I've read a considerable portion of the "establishment chapters". But rather than a simple rehashing of all the things that happened in ZSG and RBoE as a lead-in to the main body of the story, it retells pivotal scenes from other points of view--i.e. the sabotage of Utopia Planitia from the Romulans' point of view, Kasidy receiving Sisko's message at the end of RBoE, events of ZSG from Sarina's point of view. It's a storytelling device that fits a novel series that affects the entire Trek-lit universe just like in the Destiny trilogy.
The opening portion does certainly provide an appropriate reconciliation of ZSG with RBoE, where the biggest surprise was that the changing of the guard in the Romulan Empire happened before
the main events of ZSG. We now see that even though the RSE is whole again, there are still some rogue elements that the new praetor is unable to reel in.