I made the claim in 2012 that the book I most enjoyed reading for that year was the very first novel in Brandon Sanderson's Stormlight Archive series. It had a great scope, characters which I cared about (despite their lack of refinement), an incredible magic system and adrenaline fuelled action sequences. Dare I say it, Brandon Sanderson has gone one better with the sequel, in many different ways. And I'm not merely referring to the fact that this book is bigger (in word count) than the previous novel.
There are plenty of spoiler twists that I could gush about, but instead I'll talk about the improvements this novel offers over the first book. The first is that it offers a change in direction, prompting the reader to consider and question the grand nature of what is to come ahead. Yet at the same time this book is more or less as self-contained as any single book in a grand 10 book epic series could ever be. Each book, so far, leaves the reader with questions but yet at the same time does not leave the reader with a frustrating cliff-hanger. It seems to me that in taking over the mantle of epic fantasy from Robert Jordan (by which I mean that Brandon Sanderson's novels fill in the gap in fantasy previously filled by Jordan) Sanderson has learnt from some of the flaws of The Wheel of Time and consciously chosen to avoid them.
Let me therefore mention another improvement in this novel. This, for me, would have to be both the writing style and characters. In the first novel the writing was passable but noticeably rough in select places. In this novel the prose is more polished and as a result all the characters are more refined and show distinct character development. This is crucial to a grand fantasy series in my view as there is nothing worse than going from point A to point B within a series and seeing the characters remain the same by the end.
There is a distinct fluid dynamic to all the characters, made easier to note because of the more eloquent prose, in which no character is as they seem. I'm not stating that Brandon Sanderson is the greatest prose stylist in fantasy because like many other fantasy authors his prose is more of a background to the action and events of the grand story - he is similar to Jordan or G.R.R Martin in that respect (though he does not overly use more words than are required and he avoids the cursing and raunchy vibes that make Martin's work unpleasant to me). What I am stating is that there is distinct improvement in Sanderson's writing that means that his prose is neither noticeably clumsy nor noticeably purple. In other words his writing works because it does not detract from the experience of reading - this in my view is great writing.
Allow me to add to the points raised above about the fluid dynamic of the characters. The best aspect of this series so far is that I have come to realise that there are no unlikeable characters for me within this series. Characters may appear to be 'evil' and to relish evil for the sake of being, well, evil at times but the range and variety of perspectives offered throughout the novel allow for Sanderson to reveal his characters as neither good nor evil. Indeed, as I have come to realise, one of the flaws, if you will, of fantasy has been its tendency to categorically consider particular characters as good or evil in the vein of Tolkien (which works best if writing a mythology about other themes and not a pure fantasy tale). The problem with such categories is that it means you cannot truly flesh out your characters - their thoughts and motivations - and all your 'Big Bad' villains become nothing more than mini-Hitler caricatures. I do not say this flippantly or to say offence, but I am pointing out that it is easier to categorise your characters into good or bad camps, rather than explore their motivations. And while Sanderson writes about heroes and villains, he does reveal that even the 'villains' have their motivations. As such no character becomes truly stagnant or dull.
One final point about the characters of this novel. It has been pointed out by several reviewers that they believed the first book focused too much on Shallan and that she was a frustrating character in that first book. Shallan is a much improved character in this book, with some of the reasons (defence mechanisms) for her annoying nature, explained. I believe that her segments in the first book really set the groundwork for this transformation of her in this novel and also provided us with a necessary glimpse of Jasnah as a character. Where Shallan was not a particularly strong female character in the first book, in this sequel I would argue that she becomes a strong female character and this highlights that Sanderson deliberately wrote her in a particular manner that works out.
There are plenty of grand twists and revelations in this particular novel. You will learn more about the Radiants, the Heralds, the spren, the Shards and all manner of other worldbuilding items and yet come out of the book with still more questions. All I can say is that I am glad I am not the one writing this series because it is so utterly mind-bogglingly big already and there are still plenty of planned books yet to come. There are again the grand themes of the other book about honour, humanity, loss, death, life, religion and all manner of other ideas wrapped within the enticing plot (you might even spot some existentialism in there if you look).
To say any more would be to write spoilers about this series that would ruin it for the ardent fans. All I will say is that if you found the first book more or less reasonable I would pick this book up and enjoy the improvements. If you loved the first book then sit back and enjoy this sequel. And, if you are more or less ambivalent about this book or about epic fantasy as it stands, then maybe this is not the book for you. However, I fully recommend that any fantasy reader check out what Brandon Sanderson is doing - this book really connects into his wider cosmere concept - and enjoy what you see.