Today the Congregation for the Doctrine of the Faith (which absorbed my old office, the Pontifical Commission “Ecclesia Dei“) issued a decree making it possible to celebrate saints canonized after 1906 using the traditional Missale Romanum. HERE
These new (for the TLM) Prefaces are taken from the Novus Ordo Missal, which in turn were mostly from ancient sources. The standard traditional conclusions are imposed on them. Also, there are three old texts from French and Belgian sources were were in use before Vatican II. They can – not must – be used when celebrating Mass with the traditional Missale Romanum, much like even now we can use the so-called Gallican Prefaces (e.g., for Advent).
Again, these can be used. They are not obligatory. They add something, rather than taking something away.
I think this is of far less consequence or interest than the addition of possible celebration of more recently canonized saints.
Also, it doesn’t touch the body of the Missal.
Also, it is a good sign that the Extraordinary Form is here to stay.
Of interest among these Prefaces are texts for Angels and for St. John the Baptist. There are Prefaces for Martyrs and for the Feast of the Dedication of a Church, which is theologically and liturgically important the identity of a parish and those who belong to it. There are Prefaces for All Saints and Holy Patrons, and for the Most Blessed Sacrament, which might underscore the occasion somewhat better than the Common Preface. Also there is a preface for Marriage, which goes way back to the most ancient Sacramentaries (e.g., the Gelasianum Vetus).
Both this decree and the decree concerning saints will have an impact on the use of hand missals.
However, depending on the sensibilities of the priest and of the congregation these prefaces can be used. They are not obligatory.