These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Magnificent Bastard: Clarence Potter, the Confederate spymaster who always speaks his mind to Jake, runs a network of agents across the continent, and nukes Philidelphia from the back of a truck. On the US side of things, there's Luther Bliss, head of the Kentucky State Police, and the one man who scares CS intelligence (including Potter) to death.
Moral Event Horizon: Chester being a (reluctant) participant in Boris Lavochkin's reign of terror leaves him wondering if he has crossed it. Jake Featherston, Jefferson Pinkard and the CSA as a whole cross it during the "population reduction." Roger Kimble, already largely unsympathetic, crosses it when he sinks a ship after the end of WWI.
They Wasted a Perfectly Good Plot: A large number of readers were disappointed that the series is a metaphor for World War II instead of realistically examining the consequences of a Confederate victory on the world.