This is a big fat fantasy novel which is not a big fat adventure novel. It is, as you might expect, all politics all the time; national politics, court politics, bureaucratic politics (which is different from court politics). Also elf politics, by definition, as this is an empire of the pointy-eared.
Maia has a long list of disadvantages: hostile established power structures, ambitious figures who resent him, total unfamiliarity with the business of ruling. Plus the likelihood that the old Emperor's accident wasn't an accident. Plus he's mixed-race, goblin and elf, which doesn't help anything. Plus he's never kissed a girl.
He has a short list of advantages. He's got a thorough schooling in court etiquette, forced on him by his cousin, even though neither of them thought he'd ever need it. (The cousin is an ass.) He's got a sense of decency. (Just what an emperor needs, right?) He has compassion, or tries to; his personal faith is something close to Buddhism.
He's also got a damnable sense of duty, and you'll have to decide whether that's an an advantage or not. Arguably Maia's best move would have been to head for the border on page 2 and never come near the Empire again. But he doesn't even think the word "abdication" until someone shouts it at him, halfway through the book.
You have to be prepared for names. The names are polysyllabic and they fly by rapidly; the whole social structure of the Empire takes some getting used to. (It was embarrassingly many chapters before I figured out that "Osmer", "Osmin" were titles rather than personal names.) The consolation is that Maia finds it nearly as hard to navigate, so forgetting who's who is in character for everybody.
There are no quests, no magic tokens of kingship, no battles. (A few scuffles.) The book is entirely about how Maia copes with the Empire and how the Empire copes with him, which means it's a branching fractal tree of character stories and very little else. I don't always go for this kind of book, but this one is tremendously readable because all the characters are great. Some of them are nice people, some of them are bastards, all of them have interests and goals and opinions and -- peopleness. Some of them make mistakes. (Maia makes a lot of mistakes.)
The book doesn't exactly end; there's no big quest to wrap up. It has the pacing of history, rather than epic fantasy. But a very tiny slice of history; it covers less than a year, and at the end, Maia still hasn't kissed a girl. But on the other hand, it doesn't beg for a sequel. Oh, I'm sure the author could write six more if she wanted, and I'd read them. But we have met Maia and learned to admire him, and that is sufficient.