The problems with this novel begin with the first paragraph: "Let's start with the end of the world, why don't we? Get it over with and move on to more interesting things."
This paragraph is problematic for two reasons. The first is that the end of the world is more interesting than anything else this novel has to offer. That's not necessarily a strike against the novel itself – many stories use the world's end as a jumping-off point for any number of related topics – but this paragraph sets one hell of a high bar for the story, and one it is ultimately unable to overcome. As a narrative device, apocalypses unleash social upheaval on a grand, inconceivable scale. Here, that social upheaval is mostly ignored in favor of a bog-standard trauma narrative that reveals little about its central characters, substituting pain for personality. Yes, it's very easy to tell that this was published in 2015.
The second reason is the prose. I'm not opposed to fantasy stories being narrated in different modes than the highfalutin faux-antiquity register we usually get, but I am opposed to novels being written like they're being narrated by flippant 18-year-old edgelords, unless it's intentional, which is not the case here. The descriptions of geography and earthbending (it's not actually called that, but that's essentially what we're dealing with here) are well-done, and the use of second-person perspective occasionally interesting, but ask Jemisin to describe a human being and she'll tell you about their skin tone, hairstyle, and clothing, then follow that up with, "There was something strange about him, but she didn't know what."

A crap and inexplicably popular novel. Nice review.