I have to agree with most of the above, it was good but not perfect or as polished as the first two.
My other disappointment was the lack of '**** yeah' action scenes that have an emotional decision for the character. There was no equivalent to the duel from WoR or when Kalidan first picks up a spear again in WoK. The scene in Thaylen City was a small one, which I loved, and the battle in the palace to an extent but neither had me squeeling in a coffee shop as I read. The only real one was the final battle, but there was no mid-book scene. That said this book had by far the most exposition and really set us up for some loads of those moments next book.
My other criticism would be how the Skybreakers were handled. I don't think Brandon quite pulled it off, close but not there. I still don't yet root for Szethe or any of them in an anti-hero way, maybe his book will fix that. I've seen the law vs right thing done better elsewhere (Les Mis is the classic).
One criticism I keep hearing that I completely *disagree* with is Shallan's personalities. To my mind that was extremely well done and a realistic coping mechanism. I've used it myself (albeit to a less extreme extent) and it's a well documented technique for managing trauma. The way Brandon fit it into Lightweaving was brilliant, I'd love to see him explore that theme even further with other perception based magics (gold misting perhaps?).
Overall I think a lot of the 'flaws' are due to it being the middle book of the first quintet and the point where a boat load of knowledge is dropped. And we got a lot of goodies in return so I'm still happy.
Oh one last frustration, lack of chat between radiants and their spren in Shadesmer. Their banter is normally top notch and exploring those relationships in the spren's realm would have been cool. (Adolin and Maya were great though).