Firstly, Amy Welborn links to John Allen on Spe Salvi. He outlines the inital positive welcomes and reports the concerns of the decidedly "progressive" group 'Wir Sind Kirche':
The deliberately wide appeal of Spe Salvi does not mean that early reaction has been uniformly positive. The “Wir Sind Kirche” statement, for example, posed three critical questions about the encyclical:It's the first of these questions that interests me most. It's striking that Pope Benedict XVI doesn't seem to refer to the Second Vatican Council or its documents at all in the Encyclical. (Take note of that - it could be an interesting trivia question at the theological dinner table.) In particular, he doesn't refer to Gaudium et Spes, the Council's Pastoral Constitution on the Church in the Modern World. Why he doesn't would make an interesting study. Two reasons spring to mind and seem worthy of further investigation. Firstly, I seem to recall that Fr Ratzinger as peritus (theological expert) at the council was not enthusiastic about this document and was, I think, of the opinion that much of the second part of the document did not deserve to be part of a Pastoral Constitution (the most important sort of document issued by the Council.) Secondly, it might be that the whole issue of eschatology was not tremendously well dealt with by the Council and this document Spe Salvi reflects a more integrated and mature expression of the magisterium on eschatological matters. I should make clear that these are just my off-the-cuff speculations at the moment... I haven't given the matter much thought and am very much open to correction.
• Why doesn’t it rely more on Gaudium et Spes, or “Joy and Hope,” the Pastoral Constitution on the Church and the Modern World from the Second Vatican Council (1962-65), which has long been a sort of charter document for the reform wing of Catholicism?
• Why doesn’t the pope ask whether the current structures and disciplinary systems of the church actually promote an atmosphere of hope?
• Will this encyclical generate real hope for progress towards ecumenical reunion?
It is worth noting that he does draw on the Catechism of the Catholic Church in several places, and his drawing on the thought of Henri de Lubac so one could hardly accuse the Holy Father of neglecting those positive theological fruits of the Council and the Ressourcement movement. Indeed, one hopes that this encyclical will provoke a renewed interest in eschatology drawing on de Lubac's recognition of the social dimension of salvation and an honest appraisal of whether we take the reality of the Last Judgement seriously. I know that there are some of a more scholastic bent who are not fans of de Lubac, but I think he has something important to say on this issue. The idea of salvation being based around a me-and-Jesus axis does not do justice to the ecclesial dimension to salvation, and, for example, the Augustinian idea of our salvation as part of the Church which he describes as the Totus Christus or whole Christ.
Finally, I think this encyclical deserves particular attention for the manner in which it manages to incorporate some pretty serious biblical exegesis and modern philosophy in a fairly accessible manner.