In theory, there should be no problem with the Usus Antiquior under the terms of Summorum Pontificum, since the Anglican Use is a usage of the Roman Rite and not a Rite per-se. Of course, what should be in theory and what will play out in fact are not necessarily even similar, much less the same.
Putting the resurrection of the Sarum Rite (which I would love to see an option in the Anglican Use) aside for the moment, I would have been much happier if the “new books” for UK Ordinariate included a Latin text side-by-side with the English (ala the Knox Missal). That would have given a clearer signal, and would likely have precluded much discussion of the Roman Rite Usus Antiquior in the first place.
Actually the Sarum Use has not to my knowledge been part of the Anglican Communion since at least Henry the 8th or Elizabeth.
The Ordinariate liturgy is very similar to what I recall as an Anglo Catholic, and yes the Roman Canon is used and has been used for over 30 years in Anglican Use parishes. If one were to research the Sarum Use, they would find that the Roman/Gregorian Canon is what was used in the Sarum Use. Of course it was in Old English.
At least in my Ordinariate parish we are still using the BDW and at times the choir sings in Latin one or two of the short responses from the OF, maybe because they are not popular. I know that most of the AU priests involved in the new Mass wanted it to be as close to the Anglican Missal as possible and also include the Preparatory Prayers at the altar and the last Gospel, which are not included in the OF Mass. At least I can’t see our priest reciting them before Mass. Just as in my OF parish Latin is used at times in some parishes for the Gloria, and Sanctus.
I think that many of the movements that have been lost in the OF have always been practiced in most Anglo Catholic parishes. There is so much bowing of the head and genuflecting that newcomers would be at a loss the first visit.
We must remember that all the little traditions that were popular 40 years ago in the Church are no longer done and Catholics are not familiar with them. Since I have not attended the EF, I don’t know if those traditions are still in effect.
I would not assume that this is temporary and that soon or in the future the Anglican Use will become the OF. People should realize that the Anglican Use liturgy has been in existence for over 30 years and there were very few parishes. Now with the Anglican Constitution, I believe Pope Benedict made sure that it would not be done away with.
Of course many Anglicans have been saying it will, as they are very unhappy that former Anglicans have now found the truth of the One Holy Catholic and Apostolic Church.
Just as Christians in the beginning had a slow start, look at it now. The Ordinariate is growing and will continue to do so. Pope Francis has now opened it up to Catholics who have not had their First Communion or Confirmation and it has always been open to protestants who want to become Catholics through the Ordinariate.
God Bless
Bernadette