I read her 2012 book when it came out. I appreciated that she made an effort to analyze the actual music, but as you said, the defense she put forward was kind of lame. Can't say I remember much else though! Still, it is definitely one of the better metal related books I've, which speaks for the poor state of metal writing in book form. Atleast the books I've come across. One book I don't see much mention of is Andrew Cope's Black Sabbath and the rise of heavy metal music. The author points out differences between metal and rock with Sabbath and Zepellin as case studies.
The link doesn't work, is there some kind of automatic "correction" going on?