Points 3 and 4 above appear to be important not only for the present moment, but also with reference to the challenges which face us in the near future. We should be prepared to make changes: organic changes that, remaining within the Roman (“Tridentine”) tradition, are yet necessary for improving the liturgy and making it more effective in the future.
1. Careful analysis can generate serious proposals, e.g. for providing greater opportunity to incorporate Roman traditions — which are more universal than the “Tridentine” one is; or for making the liturgical forms more worthy; or to vivify them by a wise accommodation to the demands of the day or to different situations. These kinds of changes could be prepared by experts who know and love the traditional Roman rite, and are familiar with the procedure of obtaining official juridical approval.
2. In the event that current efforts to maintain the “Tridentine” rite would lead to a more extensive use of the Roman rite, we foresee a situation in which rites coexist within the Catholic Church. Other considerations lead to the same conclusion. For example, those communities of the Episcopal Church which desire communion with Rome would probably preserve the right to maintain their tradition which is based upon the Salisbury rite (or Sarum use), as transformed during the centuries of separation, but in some respects is of at least the same value as is the Roman liturgy today. Though during the past 400 years we have grown accustomed to total conformity in the liturgy, the coexistence of rites is by no means unknown in the Church. Unity is harmed not by the coexistence of clearly named, defined and controlled rites, but by confusion and individualization within the illusion of unity. The Roman and Ambrosian rites coexisted over centuries within the Catholic Church; even the Roman rite existed with local variations up to the 16th century. One and the same community may use more than one rite: an example is the Byzantine liturgy with its orders linked to the names of St. Basil, St. John Chrysostom etc., or the Episcopal Church today with clear differentiation of the A or B order in given services.
3. If the Ordo Antiquus and Novus will coexist with equal rights, then individual churches congregations and priests must be prepared to use both. If this is impossible — the differences between the two are surely greater than in the Byzantine examples mentioned earlier —, the Ordo Antiquus needs some organization to provide liturgical instruction, books, and a control mechanism. If all this can be realized quietly, without any struggle and under the direction of Rome; if unity is preserved in doctrine and discipline, and if a precondition of any approval be the acceptance of the other rite, then one need not fear any danger of schism.
Laszlo Dobszay, The Bugnini-Liturgy and the Reform of the Reform (2003)