The Holy Father clearly states the purpose of his new work, Jesus of Nazareth in the foreword to the second volume of that work. He intends to help the scientific approach to Sacred Scripture progress beyond it's limited materialistic framework which has brought it to a dead end.
"One thing is clear to me: in two hundred years of exegetical work, historical-critical exegesis has already yeilded its essential fruit. If scholarly exegesis is not to exhaust itself in constantly new hypotheses, becoming theologically irrelevant, it must take a methodological step forward and see itself once again as a theological discipline, without abandoning its historical character. It must learn that the positivistic hermeneutic on which it has been based does not constitute the only valid and definitively evolved rational approach; rather, it constitutes a specific and historically conditioned form of rationality that is both open to correction and completion and in need of it. It must recognize that a properly developed faith-hermeneutic is appropriate to the text and can be combined with a historical hermeneutic, aware of its limits, so as to form a methodological whole.
"Naturally, this combination of two quite different types of hermeneutic is an art that needs to be constantly remastered. But it can be achieved, and as a result the great insights of patristic exegesis will be able to yeild their fruit once more in a new context, as Reiser's book (Murius Reiser Bibelkritik und Auslegung der Heiligen Schrift [2007]) demonstrates. I would not presume to claim that this combination of the two hermeneutics is already fully accomplished in my book. But I hope toa have taken a significant step in that direction. Fundamentally this is a matter of finally putting into practice the methodological principles formulated for exegesis by the Second Vatican Council (in Dei Verbum 12), a task that unfortunately has scarcely been attempted thus far." p. xv
The point about the need of the method to correct itself based on its own principles was made by Cardinal Ratzinger at his historic 1988 Erasmus Lecture in New York City. Click on the link in the text above for a full treatment on that topic.