We have often joked in my house that the plot of the last trilogy is How Bren Got His Apartment Back. But honestly, I think one of the things I appreciate most about this series is how she has used the groundwork she laid with "big story" in the earlier volumes to tell "little story" here with big consequences. By the time you get this far in the series, Cajeiri's birthday party has implications that would have been completely opaque if she'd tried to start the series with it. Bren can struggle to get his apartment back and Cajeiri can have his friends for a birthday party, and these simple plots are thoroughly, completely SF.
There is still the obvious Looming Big Story Plot Point. But she's getting places with little story. I will be fascinated to see how she ties the two together at the end of this trilogy and in the next one. Any guesses on how long she's aiming for? After Protector I felt like 18 might do, although 21 would be more fortuitous and honestly I will keep reading them as long as she keeps writing them.