Probably one of the lamest books I've ever read.
1. Very amateur writing. Tons of action verbs are used over and over (nodding, explaining, asking), and the sentence structure is a bit weird sometimes. "Okay" and other modern words were used frequently in this non-modern world. And the authors couldn't even be consistent in choosing "ok" or "okay."
2. The characters were 1/2-dimensional. There are two types of people in this world: Gruff and rude, and kind and polite. Almost nothing else.
3. Unrealistic. In so many cases, it seems like the authors only experience with the outdoor world might have been roleplaying games. Small things were overlooked. For example, the main character goes to a creek and spears a fish big enough for two hungry people. Creeks don't often have fish big enough to fill one person, much less two.
4. The magic was never really explained. What rules? Why can the main character do big magical workings and then faint after small ones a few days later? Plus, he went to all this trouble to make a "river elemental", a tornado, etc. He could have just imagined that all their hearts stopped beating instead of wasting a ton of effort making an earthquake that just shook people.