Empire under glass Book

I found the book very uneven, sometimes interesting but most just boring. This book is part of a saga, which worried me at first whether I could understand the little details, since I haven't read the other books but the author explains everything. And I really mean EVERYTHING. She even repeats herself, as if the reader wouldn't remember what he/she read a couple of chapters before!
There are too many characters and each character has a story line which makes story hard to follow at times. The middle of the book (part 2) takes place during WWII as to provide us background to Evan's grandmother and who is her real grandfather. It takes almost 250 pages which the author prefers to make about Emma instead. So the real mystery only gets solved around page 500! After that, things evolve quite fast, which is a relief considering that the first 200 pages are dull and slow.
The ending is not satisfactory. Most storyline don't get a proper conclusion, they provide some but are clearly left open to new books. After all this is a saga. But what I hated was that even in the last chapters the author introduces us new developments which will only be resolved in following books. They get you intrigued but the problem is that it isn't enough to make me go out and buy the book.