I'm still working through the assault on Osiris, so to say this book is action-packed would be dead on. Based on that, I suspect I'll be about 1/2 way done with this book before this subplot is done with. Not to say that it's so much action that it's to the point of being boring, but there's a blend of backstory being placedin smaller chapters throughout the battles and the war itself is being shown from 2-3 different perspectives. So, with the jumping between characters and the backstory, I think it remains entertaining while still fully realizing the entirety of this section.
To me, often times in war movies you forget that it's even a war. Sure, they show how destroyed (insert city) is, and how its people are desperate and near death, but generally all you ever see is the perspective of a single team of people. When the focus is entirely on a single group, remembering that this is a war and there are thousands of people involved is simply not going to happen.
A (very) strange example of this would be a Where's Waldo picture. The amount of people drawn on one of those pages, the amount of work and time it took to set up this single, or double page is completely forgotten about in the split second the great Waldo hunt begins. I'm trying to avoid this, even if it's only for a moment.