Second, there is a disturbing tone in the article that suggests that Magisterial teaching is somehow less than welcome. That it impinges on our "freedom." This is foolish, and is certainly not a proposition that Josef Ratzinger would buy into. The more staightforward explanation for the non-magesterial nature of the publication, is simply that it is a work of research, historical and theological. Of course, the issues of theology embodied in the work, and the opposition to the positions of the so-called "Jesus Seminar" type historical research, is already taught magisterially in the Apostles' and Nicene Creeds.
One of the things I like about this Pope is that he does not feel the need to put his personal stamp on existing doctrines by re-expressing them. Unless it is something that is of importance - a truth that needs to be reaffirmed, for example - he keeps his personal observations personal and does not elevate them to Papal pronouncements.
BTW, when I was in Rome I heard that there is a very important document being prepared on natural law. This may not sound earth-shaking, but it will be a foundation for stating that it is obligatory for Catholic politicians to follow natural law (not Church law, but natural law, such as that which dictates union between a man and a woman, or that forbids the killing of the innocent or unborn, etc.) in their votes. The practical aspects are that Catholic politicians may not vote for things that violate natural law and, in the case of laws that already exist, are bound to do as much as possible to attenuate their effects). This is expected to be quite controversial and Italian "intellectuals" and politicians are already shreiking about it. So when BXVI does act in his capacity as Pope, he really plays for high stakes!
I think Pope Benedict is strong in the magisterial teaching. Do you think it was the author? And a Catholic one at that?