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.
Author's Saving Throw: In the afterward for Zoe's Tale, Scalzi admits that a major motivation to telling a parallel story was to make Zoe returning with exactly what the Roanokers needed feel like less of a Deus ex Machina. It also let him give some closure to the werewolves.
Old Man's War, as an homage to Starship Troopers, was naturally committed to a Crapsack World view of the universe in which humanity's only options were extinction or perpetual warfare against any race capable of occupying Earth-like worlds. (Though even in that book, the Straw Liberal'has a point' and the Consu clearly aren't following the CDF's script.) The Last Colony inverts this bleak worldview entirely, suggesting that many alien races can come to long-term peaceable agreements about territory - which leaves the CDF an example of Humans Are the Real Monsters.