(Installments aside, Seveneves needed heavy editing. Great plot, but probably about 1/3 cruft. I get it; you studied orbital mechanics & it's cool, but the 100th detailed explanation of orbital transfer is too much)
(Btw, I didn't really mind the orbital stuff in Anathem, but I found the repetitive explanations of the many-worlds idea, adding just one tiny new tidbit each time, a little annoying by the end.)
It would have been more satisfying to me if the dialog on the mountain was actually important in the context of the story at all. It was enlightening to the reader, but when Erasmus got to the convox and started talking with people, it turned out that many of them already had basically the same ideas, so he didn't really contribute anything.
Actually, it's hard to think of a point where any idea or action of Erasmus actually changed the outcome of something. He was at the center of everything, but only as a witness. Although I guess the book kind of hints that perhaps nothing that any character except Jad did had any effect on anything, since Jad rewrote it all...