I wish that Arthur had begun with his final "Inspiration" chapter and built from there, because that is where the topic of this book really comes together and seems its most focused and accurate.
Throughout the earlier chapters of this book, the content meanders instead of remaining focused on what "soft worldbuilding" really is and how it works, and seems to often operate on an incorrect definition of "hard" and "soft" worldbuilding (one that is inconsistent with that laid forth clearly in the final chapter) as well as to focus on topics that aren't really related to worldbuilding at all in the way that they're written.
This book is disproportionately heavy on quotations from published works, rather than spending its time on really exploring the concepts that the author sees reflected in those works; it feels through a lot of the book like he wanted more to show off examples of what he considers to be strong storytelling than to really explore the storytelling craft itself through the analysis of what makes those examples so compelling to him.
The chapters on character and plot also felt unfocused in relation to the stated purpose of the book. There were hints at how the author seemed to intend to relate their respective topics to worldbuilding style, but by and large they seemed like they would have been better-suited as their own pieces that focused on character/dialogue and on plot. The plot chapter did tie in somewhat better than the character chapter, especially where it tackled the issue of pacing.
I think this book had a lot of potential, and I think the final chapter is a solid introduction to the difference between "hard" and "soft" worldbuilding (the bulleted list comparison is overall very solid as an overview of the two styles) and it does a great job of focusing on the strength of "soft worldbuilding" in allowing an author's imagination to take the reins without such "left-brained" constrictions on the worldbuilding and writing process.
I would have loved to see this book go through the various tiers of professional edits (or at least beta-readers with the corresponding strengths), as a developmental editor would have helped the author really strengthen the connections he was trying to convey between worldbuilding and plot and character in their respective chapters; and a line editor and proofreader would have smoothed over the run-on sentences, misplaced punctuation, and occasional typos (such as crediting Denis Villeneuve as Denise Villeneuve) that made the book awkward to read on the surface level.
If you're unfamiliar with "soft" worldbuilding or how it compares to "hard" worldbuilding, this book may be worth picking up for its final chapter as an introduction to the concept, but I found the majority of the book to distract from rather than support its primary intent.