Build Me A Castle

A good friend of mine, and I have been reading a series of books from the YA best sellers list. They are written well, extremely interesting and once again, best sellers. My favorite part of these novels is the interesting and unique world the author has created for her stories.
It is a fantastical tale full of magic, battles between light and darkness, and the element of urgency created by the lack of  surety surrounding which character is the antagonist.
I was swept away by the premise and plot of the story from the first chapter, but soon struggled into the middle of the story. Her characters were interesting and intriguing...at first. It was enough to push me through the drooping bulk of the story. However I soon discovered that although I liked the characters, they were without personality. I was inspired by her plot line initially, but bored with it by the 100 th page. It should not require over 400 pages to follow a plot that has a lack of twists and turns. The internal conflict was real, but manufactured. The characters seemed to react to the plot. The plot wasn't driven by the character's motivation.
By the time I finished the story, I was at the least, unsettled. I liked it? I was bored? I didn't even have a favorite character. When our hero and heroine, literally sail off into the sunset, I didn't want their to be more books in the series. The bad guy got his. The good guys got away. I just didn't want to have another 400 pages of their pathetic existence to trip through all over again.
Correct me if I'm wrong, but I don't think that's what the author intended for me to feel. This author's ability to build me a glorious castle was superb. However, the story felt like walking through hollow, cold, rock corridors.
I am working hard to become the kind of writer this author already is, so I have no authority to criticize her talent. As an avid reader though, I want more.
I want my castle furnished with desperation to finish the book and read the next one. I want the walls and floors warmed with inner-conflict, passionate motivations, and a release from average.
A beautiful castle without the lush grounds, ruling class, powerful princess, and knight in shining armour, is a relic. I don't want just an interesting world. I want a living, breathing kingdom.
This has been a great experience for me because it reminds me what a great writer has to accomplish: better characters, deeper motivations, and unpredictable plots. Mastery of the craft is a lifelong pursuit, I know that.
For now though, I will use what I am learning to build better castles...and then kingdoms.