One has only to look at the violence of the Reformers' rejection of the mass as it was then popularly regarded and celebrated, and at the radical attempts many of the Reformers made in bringing the liturgy into line with the scriptural data as then understood, to appreciate the position Trent found itself in as far as the liturgy was concerned. The council indeed initiated some reforms, but in the long run a consensus prevailed in the council itself and in the counter-reformation church that the problem was so emotionally charged and so vast as to require serious action only at some later and more propitious date. This date, infelicitous though it may seem to some, is our own era- an era that has, due to its own tenor and needs, precipitated the unresolved problem of liturgical evolution in even more critical terms than in the sixteenth century.
This was written in 1967, just after Vatican II and towards the beginning of the massive postconciliar liturgical reform that occured in Roman Catholicism... this was also Kavanagh before his substantial disappointment with how the reform of the rite of initiation played out and some of his more controversial writings about the origins and reform of confirmation. Even here, however, his aggressive style of identifying areas of Church life in need of reform, along with the historical trajectory to vividly contextualize current problems, is present. This is what has impressed me the most about Kavanagh since discovering his work. Whether or not he convinces me in all of his historical arguments, there is a sense of coherence in thought about the structures of the Christian life, an awareness of various strands of tradition that is often absent in other scholars. Josef Jungmann is another liturgical scholar that I think displayed the same sort of acumen.
Kavanagh is also goad to theologians. He wrote at one point with regard to Geoffrey Wainwright, "Dr. Wainwright is without doubt our most articulate and graceful evangelist to that tribe of intelligent people usually called systematic theologians." The evangel presented to that tribe, of course, was that liturgical theology is first theology, and systematic only second. One can disagree with that sentiment, but there's no question that the careful work of liturgical scholars like Kavanagh should be taken with the utmost seriousness by those of us who are engaged in more systematic aspects of theological reflection. Theoria can often subsume the complexities of life and practice with the aesthetic smoothing tendencies of its systemic grasp, and we would do well to pay attention to where we might be guilty of these liturgical... or other... abuses.