A globe trotting fantasy epic that breaks many conventions. The world is a fuzzy mirror of our own during the late medieval period, but there seems to be little colonialism and a broad racial diversity among the elites. Women seem to hold high status positions, both political and martial, with little discrimination. Sexual preference seems to be well tolerated but there are still arranged marriages intended to establish strong lineages. Altogether these make for a fantasy world that can focus on the cultural differences between different parts of the world, and tells a grand story about people putting their prejudices and self interest aside to tackle a global existential threat, the sort of thing we can probably do with more of.
My critique is that lineage and class are not really treated with the same critique, relying on more traditional chosen one heritage tropes. There's some lip service towards disrupting this at the end of the book, but it's fundamental to the plot: the crisis is resolved due to the heritage of the protagonists as well as their actions, so it ultimately servers to reinforce the importance of lineage.
That said, this is still a great achievement and definitely worth a read, you could consider it as a shorter, better Song of Ice and Fire or a millennial Lord of The Rings.