The language of # 17 of Gaudium et Spes was called by Ratzinger, "downright Pelagian", and I'm shocked that I didn't notice it until re-reading it. My Pelagianism sensors are probably on the fritz with it's overabundance in many parts of the Church. Anyway, of what I've read so far, while I will admit it is overly optimistic, I feel like it makes up for this in it's pastoral nature.
I also find it interesting that the current Pope called a conciliar document heretical in language/emphasis. It gives me a better sense of how one can feel about certain decisions in the Roman Church and still remain orthodox. Alot of my doubts about Peter Kreeft were lessened after that.
I found an interesting article on the whole thing here: http://www.firstthings.com/article/2008/08/from-ratzinger-to-benedict---17