As a book itself, The Bonehunters is largely inaccessible to anyone who hasn't read the preceding five books. It follows the 14th Malazan Army who, under Adjunct Tavore, were denied a battle against the Sha'ik in the Holy Desert in book four, House of Chains, and who now pursue its remnants to the city of Y'Ghatan and lay siege to it. With the forces populared by survivors of the Bridgeburners (Gardens of the Moon and Memories of Ice) and survivors of the Chain of Dogs (Deadhouse Gates), the newly christened Bonehunters struggle for identity and purpose as their Empire changes around them. Which, as an introduction, should be fairly confusing, have no frame of reference to you and essentially leave wondering why you should read the rest of this post.
Which is why most of this post will discuss the series as a whole (so far).
As a sixth book, Bonehunters suffers structurally from being one of the books in a large sequence where a lot of changes have to happen and where a lot of strands are bought together from the proceeding five books. It is a big book at 1200 pages. It is big and feels big but at the same time, it feels like one big turning circle and you can feel that by the end. Outside that, the narrative ticks across all the books continues, where at times Erikson plays his secrets a little too close and the meaning of events and characters a little too obscurely, but your mileage will vary on that.
But beyond that, what works is still there, still strong. What is most impressive about Erikson's series is the consistency of the world building, the sense of completeness that exists in it. A lot of fantasy novels are, by and large, a vague European medieval setting, in which personal hygiene is of a higher standard than it once was. In a grand generalisation, a lot of the books take the historical props, the vague attitudes, the vague morals, and some swords. It is never as messy as real history, nor as detailed, and frequently, there's a dragon (but infrequently, black people and independent women). Erikson, who has been an anthropologist and archaeologist, draws heavily from history as well--it is hard not to draw a line between his use of Gods in the series and those of the Greek Gods in various myths, legends--but it is a messy, grey shaded world, heavily multicultural, multi-gendered, multi-sexuality and the vast amount of diversity in it speaks to the many cultures and ways of living that exist on the Earth.
I would not argue that Erikson is using his series as a mirror for anything in our society, however. His world, heavily detailed in cultures and characters, is an insular thing in that fashion, but in the way that our world itself is a varied, multi-layered being, so is Erikson's, and his ability to portray that throughout all six of his books so far is, I believe, his singular most impressive feat. It is worth reading the series alone, in my mind, to watch him build the world, to watch him layer and cut it, to show this angle, then that. It is worth reading the series of the sense of immersion that arises from his skill of world building. All of which must seem like a strange thing to say, since it is not often that such a thing is said about a ten book series, not to mention the fact that in saying so I can avoid noting that the narrative of a retreating army in Deadhouse Gates is done superbly, Memories of Ice is utterly hearbreaking, and Midnight Tides has an excellent set up that is let down only because its final quarter can't equal it... but there you go, I have said it.
I dig it, as they say.