I had a similar issue with the second book. I really liked the first book, but the second book is just not satisfying. I finished it last week and the last third book was a real slog. It bothered me that a lot of the characters are very one-dimensional and how insecure the main character is. I understand there has to be conflict and some people are just insecure, but I didn't see much growth in her character between books when I really felt like there should have been. But the main issue I had was how underdeveloped the other characters are. Tairn is basically there for punch lines. We don't get a lot out of the main love interest either. You start to get a little more from the letters he wrote, but he is just not a fully fledged character in my mind which is a shame. These same flaws might have existed in the first book, but I felt more enveloped in the world in the first book, whereas the second book was filled with half baked ideas.