Pope Pius XII continues in Mediator Dei with the importance of the centrality of Rome for making substantial changes in liturgy:
65. In every measure taken, then, let proper contact with the ecclesiastical hierarchy be maintained. Let no one arrogate to himself the right to make regulations and impose them on others at will. Only the Sovereign Pontiff, as the successor of Saint Peter, charged by the divine Redeemer with the feeding of His entire flock,[Cf. John, 21:15-17] and with him, in obedience to the Apostolic See, the bishops “whom the Holy Ghost has placed . . . to rule the Church of God,”[Acts, 20:28] have the right and the duty to govern the Christian people. Consequently, Venerable Brethren, whenever you assert your authority – even on occasion with wholesome severity – you are not merely acquitting yourselves of your duty; you are defending the very will of the Founder of the Church.
We are not surprised at this important quality control effort. For many liturgical practices, I’m not sure we can quite say they are the will of the Lord. Where the Holy Spirit has led, perhaps. And from them the Spirit may continue to lead us further.