I think the system was revealed a little too early, and someone like me will try to decide what the system is right away, rather than patiently waiting for the author to fully explore the idea. So it does feel a little long, but I'm not sure it's a flaw. I have felt the same way about gimmicks in other well-regarded and much longer writing (400 page books that give away the whole thing in chapter 1), but here it seems balanced enough. Part of why it felt too long to me was just because the people in the story are boring, although I think that is also intentional.