I find Neal Stephenson to be a bit condescending, perhaps even patronizing. Reading Seveneves (and Stephenson in general) is a little like being cornered by a socially awkward geek who just has to tell you about this amazing cool new technology thing that they’ve been researching or working on or whatever. This is not a serious problem since he really does have some amazing things to tell you about.
Some writers don’t sweat the details of technology in their stories. Some writers do sweat the details, but don’t burden the reader with them; they simply keep things legit. In Seveneves, the technology is the point. What others would leave to an appendix or a footnote makes up the bulk of the text. A lot of science fiction introduces one new thing to our universe, be it technological or social or biological, and then asks the question, what would happen next? In Seveneves, Stephenson doesn’t restrain himself to one new thing. He just keeps throwing new technologies and new possibilities on the pile. The story he weaves with these is perhaps underwhelming, but it is just one possible story. The world he has written is much larger and more inspiring than this one narrative. He has dumped a pile of Lego at your feet, built a respectable starship, and then handed it all over to you.
For the most part, I find Stephenson’s characters forgettable. He treats them too much like his technology I think. They are theoretically possible, but he describes them with a sort of clinical detachment. Even when we are inside a character’s head, we simply observe their thoughts and emotions. We do not share them. There are occasional glimpses of humanity, and these are wonderful and clever, but overall I am left with little emotional connection with his characters. I am only interested in watching what they do to see the plot advance.
I would be remiss not to mention that Seveneves plays out in two or three acts depending on how you’re counting, and the transition to the last act is difficult. He essentially starts a new book two thirds of the way through the volume, and even with the monumental thickness of this tome, it feels a little cramped.
Do not be fooled by my criticisms; I enjoyed Seveneves. Its scope is tremendous, it has some memorable scenes, and it provoked (and continues to provoke) many thoughts. The characters may not have roused emotions from me, but the story did. Stephenson may have prattled on a bit much about orbital mechanics, but I am totally in to orbital mechanics.