There is the idea that Vatican II was a discontinuity with the past. Ratzinger taught us the idea that Vatican II was continuous with the past faith that there was no rupture. This hermeneutic of continuity does not mean that the Church did not change its focus or outlook though. Think about it, if you go into any library you may find a collection of the Church Fathers. This collection may well be divided into post and pre-Nicene fathers. Is that done simply because the council of Nicaea was a great way to arbitrarily divide history? Or did the outlook and vision of the Church change through that council and through Constantine era, such that it is proper to speak of different outlooks for the faith?
Similarly, with the council of Trent according to many traditionalists. “Trent meant a significant change from the lack of clarity of the previous theological tradition. It is also known that the success of the Council of Trent in creating what we now call the Tridentine era was the result of discontinuities between the letter of the decrees of the council and the application of those decrees, that is, the council’s spirit in the post-Trent Church.”(Vatican II: The Battle for Meaning, by Massimo Faggioli) Step back and think. I we speak of Trent as a great clarifier and creator of the Tridentine way, then that automatically means before and after it things were different in the Church. There was a discontinuity in practice and in outlook. How could it not be? Why would you need a council to define and change things if there was no ambiguity and need for clarification?
A great change that occurred through Vatican II, was the Church removed the unhealthy habit of viewing the faith in terms of Trent and was able to view Trent in terms of the faith. Trent was one piece in the history of the Church. Its ways were one way of doing things which tied up with the faith were not the faith per se. Vatican II enabled a return to ancient roots (often missed by Trent) and the ability to judge and access the world in term of the faith not simply by what others did 500 years ago but what tradition taught for 2000 years!
Hence, yes Vatican II, Nicaea and Trent were not discontinuous in that they taught a new faith, but they did create a new way of seeing and living it out! There was a break in outlook and view.
Jesus himself, did not destroy the law -but fulfilled it. Jesus caused the law to be viewed in a whole new way (the way it was meant to be) and then added unto to it his own law of the spirit which is love.