The following passage from MD is almost prophetic, for this is exactly what happened following V2.
60. The use of the Latin language, customary in a considerable portion of the Church, is a manifest and beautiful sign of unity, as well as an effective antidote for any corruption of doctrinal truth. In spite of this, the use of the mother tongue in connection with several of the rites may be of much advantage to the people. But the Apostolic See alone is empowered to grant this permission. It is forbidden, therefore, to take any action whatever of this nature without having requested and obtained such consent, since the sacred liturgy, as We have said, is entirely subject to the discretion and approval of the Holy See.
61. The same reasoning holds in the case of some persons who are bent on the restoration of all the ancient rites and ceremonies indiscriminately. The liturgy of the early ages is most certainly worthy of all veneration. But ancient usage must not be esteemed more suitable and proper, either in its own right or in its significance for later times and new situations, on the simple ground that it carries the savor and aroma of antiquity. The more recent liturgical rites likewise deserve reverence and respect. They, too, owe their inspiration to the Holy Spirit, who assists the Church in every age even to the consummation of the world. They are equally the resources used by the majestic Spouse of Jesus Christ to promote and procure the sanctity of man.
62. Assuredly it is a wise and most laudable thing to return in spirit and affection to the sources of the sacred liturgy. For research in this field of study, by tracing it back to its origins, contributes valuable assistance towards a more thorough and careful investigation of the significance of feast-days, and of the meaning of the texts and sacred ceremonies employed on their occasion. But it is neither wise nor laudable to reduce everything to antiquity by every possible device. Thus, to cite some instances, one would be straying from the straight path were he to wish the altar restored to its primitive tableform; were he to want black excluded as a color for the liturgical vestments; were he to forbid the use of sacred images and statues in Churches; were he to order the crucifix so designed that the divine Redeemer's body shows no trace of His cruel sufferings; and lastly were he to disdain and reject polyphonic music or singing in parts, even where it conforms to regulations issued by the Holy See.
63. Clearly no sincere Catholic can refuse to accept the formulation of Christian doctrine more recently elaborated and proclaimed as dogmas by the Church, under the inspiration and guidance of the Holy Spirit with abundant fruit for souls, because it pleases him to hark back to the old formulas. No more can any Catholic in his right senses repudiate existing legislation of the Church to revert to prescriptions based on the earliest sources of canon law. Just as obviously unwise and mistaken is the zeal of one who in matters liturgical would go back to the rites and usage of antiquity, discarding the new patterns introduced by disposition of divine Providence to meet the changes of circumstances and situation.
64. This way of acting bids fair to revive the exaggerated and senseless antiquarianism to which the illegal Council of Pistoia gave rise. It likewise attempts to reinstate a series of errors which were responsible for the calling of that meeting as well as for those resulting from it, with grievous harm to souls, and which the Church, the ever watchful guardian of the "deposit of faith" committed to her charge by her divine Founder, had every right and reason to condemn. For perverse designs and ventures of this sort tend to paralyze and weaken that process of sanctification by which the sacred liturgy directs the sons of adoption to their Heavenly Father of their souls' salvation.