VL 46-51 covers the sub-topic “necessary prudence.” In other words, just because something can be done doesn’t mean it should be done. A first appeal to Vatican II and everybody’s favorite (and unique) nod to organic development:
46. “Innovations should only be made when the good of the church genuinely and certainly requires them; care must be taken that any new forms adopted should in some way grow organically from forms already existing.” (SC 23) This norm was given in the constitution Sacrosanctum Concilium in relation to the restoration of the liturgy, and it also applies, in due measure, to the inculturation of the Roman rite. In this field changes need to be gradual and adequate explanation given in order to avoid the danger of rejection or simply an artificial grafting onto previous forms.
It’s a high bar. Requirement must be genuine and certain. Less troubling is the notion that new forms should develop from old. The (in)famous Agnus Dei tropes are an example. The Fraction Rite, at times, must be extended. So the genuine need is present. But since the old form permits more than a threefold repetition, it is less certain that employing tropes is a good idea. This, in spite of the traditional form of many litanies in the Catholic tradition.
Interesting also the appeal to a “danger of rejection.” This, before the days of English MR3.