This one was a significant step down from Volume 14. There is nothing wrong with a routine adventure - in fact, most of the Goblin Slayer light novels are routine adventures, with the biggest ones being the most exciting. However, this one was just less interesting.
Premise: a centaur princess runs away from home, her best and closest friend comes trying to find her since she never wrote back. There is chicanery involved which leads to a mild mystery. The problem is that I didn't care for a single one of the centaurs, which severely undermines the entire book. I do have a bit of empathy for Baturu's point of view, especially because I think she's right, but that's not enough to salvage her after her introduction.
Overall, Goblin Slayer continues to develop slowly, with one of the best scenes very early on in the light novel involving Goblin Slayer and Cow Girl's Uncle. Besides these small interactions, this one does not have much to recommend it and is a middling experience.