I think the 'gothic' production works remarkably well, really matching the subject matter and lending a high quality aesthetic to the book. However what I mainly wanted to say was in agreement with your pointing out how small the type is. It really does affect readability and was a very poor choice and mistake by the publishers on this occasion.
For others, if you wish to mainly read about the history of charnel houses and ossuaries and are concerned about any overly small text, please be warned here before any purchase. Many of the photos, and more that are not in the book, are freely available on the author's website. However, if your eyesight is very good or if you mainly wish to have good photographic reproductions then the reproductions in the book are of excellent quality and it is to be recommended.