No spoilers here. I am still reading the book, and am around page 125.
One thing about a sequel book is that, if it builds on top of the events that happened in the previous books, it needs to remind the users what happened. This is quite a challenge I am facing when reading many concepts and names that I do not remember anymore. It's been more than a year since I read the last book, and noone should expect me to remember all the events and characters (especially not so important ones) from that one.
I remember complaining about the exact opposite when I was reading book 1, 2, and 3 back to back. Book 2, repeated many of the things that happened in book 1.
I wonder where that fine line is?