I have a couple of counterpoints to this that I'd like to address. I haven't had a change to read through all of the comments and address them individually, but I'll try and point out a couple of things that I think need corrected from the article above and my own on io9.
The first, major point is that no, I don't want Clausewitz to write science fiction. After reading his works for my Military Thought and Theory course (I've received an M.A. in Military History from Norwich University. For my own disclosure, I work for the school and that specific program as an administrator for the students, but the Masters degree really pushed me in terms of what I knew and how I understood the military), I think he's one of the more dry reads that I've yet to come across, and that while there is a lot of outdated information in the book, given the advances and changes in how militaries operate, there are some elements that I feel work well, conceptually.
The main point in the article wasn't written to say that military science fiction had to be more like a Warfare 101 course in how future wars should be fought - far from it - but that military science fiction could certainly benefit from a larger understanding of warfare. As you note, there's a lot of military themed SF stories about the people caught up in warfare, ones that examine how they perceive warfare, and how warfare impacts the individual in any number of ways. This comes in a couple of ways, one story related, the other more superficial.
There are very few (I can't recall any that specifically look to this) military SF novels that look at warfare in the same context. While I agree that stories are about characters, it's also the challenges and the subsequent themes that embody their struggle that makes a story relevant and interesting to the reader. This, to me, as a reviewer and reader, is the element that will set up a book for success or for failure. Characters, the story/themes/plot, and the challenges that face him all work together to form the narrative. What the characters often learn from their challenges is what the reader should also be learning, and this, to me, is a missed opportunity for some elements of military science fiction. A majority of the Military SF/F stories out there have the characters impacted, but warfare is generally painted as a element of the narrative, not something in and of itself that can be learned from.
Superficially, wars are incredibly complicated events, and often, I don't feel that they're really given their due in fiction. There are a couple of points that I want to make in advance of this – this doesn’t mean that I want or require more detail on every element of warfare, from how the logistical setup for an interstellar war might be put into place, or how the X-35 Pulse rifle is put together to best minimize weight requirements in order to be effectively shipped through lightspeed. Those sorts of details aren’t important to the character’s journey in this, and they add up to extra fluff, in my opinion. Weapons and systems put into place for warfare are great, they sound great, and the same arguments are put into place in politics today. What makes the better story, in my opinion, is a better understanding of the mind behind the sights, from that individual soldier’s motivations to his commanding officer’s orders and training, and how war is understood on their terms. In a way, world-building for any story should firmly understand just what warfare is, or at least come to a consensus within the author’s mind as to how it will be approached.
Oftentimes, generals are accused of fighting the wars gone by. That’s certainly true in the ongoing conflict in Iraq/Afghanistan, and why there was quite a bit of resistance in shifting the military’s focus over to a counter-insurgency war, rather than one of armored columns and maneuvers: generals fight with what they have, and what they’ve trained for, and changes come afterwards. Starship Troopers, The Forever War and Old Man’s War all do the same thing, and that’s not really what I’m arguing against – the authors wrote what they knew – Heinlein, undoubtedly from his experience with the Second World War, Halderman from his own experiences in Vietnam, and Scalzi from observation and research. Science fiction looks to the future, but unless you’re a dedicated expert in a think tank, there’s really no expectation that these books will be predictors of the future, but also aren’t necessarily going to be good at the military thought and theory behind the battles on the pages. Will the individual soldier know anything about logistics and engineering solutions? Probably not, but those things certainly will influence how that soldier is operational on the battlefield, which will undoubtedly affect his view and outcome on the battlefield. While these elements might not surface in the text, they should be understood.
Art is formed within the context of its formation. I don’t believe that a book written in the Post-WWII world should be really in depth on theoretical warfare on the character level, nor should it look beyond what the audience and writer really understands. However, as times change, context changes, and books are understood differently. There is no doubt in my mind that we will see science and speculative fiction stories in the next decade that are directly impacted by our understanding of the world since 9-11 and the warfare that has come as a result, because the current and budding writers are also changing their views on the world.
I see most military science fiction like I see some types of military non-fiction. Stories like Starship Troopers are like Band of Brothers. They’re fun and good character stories, but anything by Stephen Ambrose is certainly not serious military nonfiction, and isn’t something that I would use to better understand the nature of the Second World War. Looking at a similar book, The First Men In, by Ed Ruggereo, is a better example, (one that I recommend highly, as a counterpoint), but that tells a good character story AND looks at the strategic nature of Airborne operations during Operation Overlord.
Military Science Fiction can best be summed up as soldier science fiction, with the characters learning much about themselves and society – that’s never been in dispute from me. What I would like to see someday added to a field is a novel that better understands the nature of warfare, and extrapolates some of the lessons that can be learned from it.