I really could used more info about mankind and its status in general.
Actually Petro deliberately shafted humans out of the spotlight to focus on the aliens. It's one of the more unique traits of UAW, an alien attack on Earth where the focus is on the perspective of the various alien factions involved rather than focus on human perspective which is what has been done in various sci-fi ranging from War of the Worlds to Halo Wars.
What I do wish was that the story was more detailed. Adam Isgreen couldn't be more right when he said that the addition of the Masari compromised the storyline... especially thanks to their huge slew of filler missions. Nufai's fate is ambiguous, Vertigo disappeared after the Novus campaign, we never really understood how the Arecibo observatory was supposed to defeat Kamal aside from a vague statement that his forces would magically surrender...
...and did I mention the filler missions? going across 2 entire continents before the more significant battles is too much. Way too much.