As I understand it, the book was designed as a study book for newly interested. There are Kingdom Ministry articles advocating starting studies in the book. I do not know how successful that was.
It wasn't meant to be an academic study. As far as I can tell, no Watchtower product was meant to appeal to academics or meet that kind of standard. They're all meant to gain adherents and to project the Watchtower's theology. So It's no surprise that someone expecting an academic product is disappointed.