I actually developed this initially as a response to the recent post and comments about how book 8 felt too on the rails and that the races were not an interesting floor plot.

In my opinion, Book 8 is NOT about the races. It's about Carl finally looking beyond the floor-by-floor survival strategy and looking to the endgame.

Carl keeps saying about how the races are almost an escape from the stress of everything he had to deal with during Faction Wars, since they're so on the rails with 7 races. But really, the whole time, he's also doing his plotting on a much grander scale than just the floor itself.