Take Walter H. Hunt's The Dark Wing for example. The cover fits the check list completely, and the story starts in a familiar milieu, the human Empire that's been at war for centuries with an implacable foe. Starships travel between worlds in days, and weapons are designed to combat powerful shields, turning battles into slow tests of brute force.
All familiar tropes, and we're not surprised when a peaceful fleet mission to a new naval base on a remote colony world is attacked by the enemy, ending decades of peace in a tactical strike at the heart of the navy. But then things start to slide away from the familiar. The admiral sent out to deal with the enemy is an academic, with cultural and psychological theories as to the reasons for war - and a possible strategy for ending it once and for all. It's a strategy that goes against all that the military has been taught, and all that the political forces back on Earth want to believe. It's a strategy that will win the war, and change human and Zor societies completely.
Religion and culture rarely have a place in military SF. It's usually a monolithic human state against the universe (or at least against itself) - so aliens are just another bug hunt, cardboard characters set up as targets for the coruscating forces of hi-tech weaponry. Sure, occasionaly we'll get Moties or K'zin, but generally it's just a galaxy full of cardboard cutouts. But here Hunt has gone the whole hog, coming up with a consistent background for his winged Zor - from the Zorastrianism-tinged religion that's at the heart of everything they do and are, to the web of nests that govern the day-to-day running of their world.
It's been about time that the moral ambiguities of the new wave of space opera met the certainties of military SF. The Dark Wing takes the familiar militaristic story and twists it, subtly at first, but by the end of the novel everything we have expected has been overturned. Nothing in Hunt's universe is what or who it seems - loyalties are complex, and events conspire to change the way we look at the his world. The war may well be over, but there are more questions to be answered in the rest of the series.
An interesting first novel, and a writer to keep an eye on.