Interesting way of handling VatII. Much of the article seems to say precisely that it is a breach, but this is something that cannot be said openly. It would be a direct indictment of the powerful people who engineered VatII's "reforms" and kept them in place even though it was obvious that they were driving Catholics away from the Church in droves, and might even bring up questions of the validity of the Mass in certain places and times.
Ratzinger himeself was involved in the initial VatII liturgical "reforms," btw, but he seems to have realized very early that the direction the "reforms" were taking was seriously wrong, and since then has worked to restore things to their proper places.
In terms of the liturgy (and many other things), I think VatII was a serious breach, but for the sake of harmony and the future, we're going to have to simply pass over it as a "development," hopefully leading to another "development" in the near future where the Roman liturgy is restored in a more traditional form.
I had heard that he was involved, but I believe the movement for liturgical reform was underway at least by the 50s, before VatII. (Lucile Hasley mentions it in an essay from that time, and we were learning sung "responsorial psalms" in school by '58.) I expect different people for reform/"reform" worked and hoped for very different things. I would find it difficult to believe that Ratzinger was ever a contributor to the self-glorification that other posters have mentioned (which seems to be fading in recent years, though not enough).
It's significant that R. was at Regensburg, which was home to the major liturgical music reforms which began in the late 1800's.
Those reforms were more oriented toward 'housecleaning' than toward revolution--sort of the difference between defragging your C drive and re-installing Windows.
Although the document on the liturgy was "clean" on the surface, and R approved it, it was the implementation, run by Bugger Bugnini, which was the problem.
R became aware of the disastrous wording of the DOL just a little late, after Bugnini & Co had loosed the hounds of Hell.