The book misses on a few counts.
First, had AD 70 been the final coming of Christ, the early followers would have experienced it at the cognitive and personal level and passed that info on. The event was kind of a big deal and could not have been left out of the early discussions and doctrines. So, this book's thesis doesn't pass the most basic smell test.
Next, the arguments about tradition vs. Sola Scriptura are much ado about nothing, as Sola Scriptura is also a tradition and is not something mandated in scripture. (Sola Scriptura is an assumed principle hatched during the Reformation.) So, if some people insist that early church history matters regarding eschatology, they have a valid point. I see no reason that the Sola Scriptura tradition of the 1600s should trump the all-is-not-finished tradition of the first four centuries of church history (and every century since).
Finally, the matter can never be settled, even if one assumes Sola Scriptura. All scripture was written prior to AD 70, and scripture lacks a written confirmation after the fact. So, the bible is basically silent on the matter, and everything else is extra-biblical speculation. (And who can be dogmatic about extra-biblical speculations?) This dilemma could have been averted if just one book had been written in AD71 saying, "It's all finished - every last bit." But alas, scripture was written prior to AD 70, and every eschatological book of the New Testament is forward-looking. So, no one can ever know for sure if all is complete, especially those who swear by Sola Scriptura.