Funnily enough, Mark Waid has been talking on Twitter tonight about plot being overrated. (It's not threaded, but
here's his Twitter account.)
Different people have different tastes, of course. Some like deep, intricate plots full of all sorts of twists and surprises. But for the most part, plot is largely dressing. Some of the most critically-acclaimed stories ever have had paper-thin plots. Same with some of the most commercially-successful: Waid pointed to the Bond movies as an example of that. He retweeted someone else who brought up the Deadpool movie as having a really simple and cliche plot. Waiting for Godot is considered a classic of theatre, and the plot is literally two guys talking.
What matters most in a story is the emotion. If it gets you to feel what it wants you to feel at any given moment, whether that be happy, sad, scared, angry, excited, whatever. That's what the story is. Plot is just one component.
I've said before that I would read a series about superheroes getting together for coffee. I'm not joking. Because a good writer could do more intense character exploration and drama in 8 pages of coffee than in a year of plot-driven stories.
But like I said, it comes down to taste. If you want a deeper plot, then this probably isn't the book for you, because Whitley's making it clear that this is very much a character-driven series.