This is a hard thing to write since I am a fan of David Weber's work. Honor Harrington got me entranced and so did Colin McIntyre. Until now the only time Weber has disappointed me was with Apocalypse Troll, well add Off Armageddon Reef to that list.
First off, I did not care for any of the characters in the book. That is a tough hurdle to surmount. I could not identify with anyone since it was abundantly clear that Nimue had a mission and she would have to use people to accomplish it. And unlike Sean, Harriet, and their friends on the planet Pardal having this urgent need to contact home while being wracked with guilt over what they are forced to do to accomplish that in Heirs of Empire; there is no immediate need with Nimue's mission, which is to drag Safehold to a technological level high enough to rid the universe of the Gbara which have annihilated humanity from the universe except for this hidden colony nor does Weber really dwell that much on Nimue's guilt. Again I am reminded strongly of Colin McIntyre's struggle to get Earth ready for the Achuultani assault in The Armageddon Inheritance. Or even when Birhat, as the last human settled planet of the Third Empire created the Fourth Empire to oppose the next Achuultani invasion. This book never overcame in my mind the many similarities it had with previous Weber books. And catching Weber in a historical goof really kicked me out of this book, there was no Xenophon at Salamis. Think of another name starting with X.
On the bright side this caused me to dig out David Brin's second Uplift Trilogy which starts with Brightness Reef. We find the conflict that the Terran survey ship Seeker accidentally created by finding an ancient fleet in the Shallow Cluster in Startide Rising has spread to a fallow world called Jijo. On Jijo Terra has created a secret colony in case races such as the Soro wipe out humanity. On Jijo are other races in hiding and with the humans they form a common government. We get to follow the further adventures of Dr. Gillian Baskin, reluctant commander of Seeker, the Niss machine, and the tattered hard-pressed remnants of Seeker's crew while being introduced to such new characters as Huck, a hoon raised G'kek, or Sarah, a human of the Jijo colony, who has figured out there is a great rupture about to unravel the Five Galaxies. I much prefer reading again Sundiver, Startide Rising, The Uplift War, Brightness Reef, Inifinity's Shore, and Heaven's Reach since there is so much 'what if' to explore in the universe of the Five Galaxies and Brin invites us in. I found no 'what if' or even wonder in Weber's book.
Or if we want to explore a human settled world that has regressed to pre-space flight technology, in fact to 19th century technology there is always King David's Spaceship by Jerry Pournelle. We see the planet Samuel's World scheme and plot to acquire the technology for a spaceship so when they request admittance to the Empire they won't become a satrapy. To do so people from Samuel's World travel to an even more primative planet that has a pre-collapse Co-Dominium library the locals have no idea of how to operate. The Empire of Sparta though has some rules when dealing with more primitive planets, one of them is one can not use technology greater than what is already on the planet. Which is why the heroes must use subterfuge to get their spaceship technology. In the end they do get their spaceship and admitted to the Empire while our brave heroes are charged by the Spartan Navy with violating the technology edict. Their crime? Introducing horse collars on that world with the library, which made horses far more efficient than slave labor.
The inspiration for some of Jerry Pournelle's work can be traced back to a previous master of science fiction, a fondly missed gentleman named H Beam Piper. Piper twice visited the concept of a church that had the world wrapped around its finger; in the Kalvan Paratime universe the story is called the Gunpowder God and in his TerroHuman Future History as When In The Course. In both cases the church in question has discovered the secret behind gunpowder and uses that knowledge to leverage it's way to dominance except for a small rebellious kingdom. In Weber's universes this rebellious kingdom is called Malagor in Heirs of Empire and in Off Armageddon Reef it is called Charis. And Piper writes from the perspective of the rebellious kingdom as they set out overthrowing the tyrannical church. For When In The Course, Piper tackled a whole planetary rebellion lead by the kingdom Hostigos in a mere 180 pages along with sketching some vivid characters. Off Armageddon Reed is over 600 pages and is not even finished. Sometimes more is not a good thing, like super-sizing a meal from McDonalds.
Alas since I bought the electronic copy of Off Armageddon Reef, there is no way to put it on eBay in an attempt to recover some of my expense. Which is a pity.