This from about.com agnosticism/atheism about prayer and belief is very well put:

According to Catholic tradition, lex orandi, lex credendi [means] the law of prayer is the law of belief. What this means is that how a person worship[s] not only shows what the person really believes, but that how a person worships can ultimately decide what that person really believes.

Hence the importance of liturgical nuance:

As people’s patterns of actual worship change, so will their underlying beliefs – even without their realizing it. It is because of this that the Catholic Church can be so strict in maintaining what many might regard as superficial practices, causing them to be seen by many as old-fashioned and tyrannical.

The hierarchy realizes that allowing even minor changes in the practice of worship could lead to unforseen and unintended changes in beliefs, and the Church is one organization which understands how to think about how things will turn out over very long spans of time.

The author’s intent may be to show how we sheep are manipulated by our shepherds, but it’s an honest statement and quite accurate as taken to show how bishops fulfill their mandate and the deposit of faith is preserved.

I am reminded of one of the late Ralph McInerny’s novel about the Soviet mole who after years in a monastery was converted by the daily chanting of the divine office. (Anybody out there know the name of that book?) Prayerful repetition has its effect, as in J.D. Salinger’s Jesus prayer in Franny and Zooey.

I think today’s priests who insert subtle changes into the words of the mass have this in mind. They have their theology and want to promote it.