I thought that I’d start with “the Mystery of Faith”, just after the consecration of the precious blood in the ordinary form. Even in the Latin, there was some controversy when the ordinary form first came out, as the words “mysterium fidei” were moved from their position in the words of consecration. Compare the Latin of the older extraordinary form and the newer ordinary form.
Extraordinary Form: Accipite et bibite ex eo omnes: hic est enim calix Sanguinis mei novi et aeterni testamenti: mysterium fidei: qui pro vobis et pro multis effundetur in remissionem peccatorum. Haec quotiescumque feceritis in mei memoriam facietis.
Ordinary Form: Accipite et bibite ex eo omnes: hic est enim calix Sanguinis mei novi et aeterni testamenti, qui pro vobis et pro multis effundetur in remissionem peccatorum. Hoc facite in meam commemorationem.
New Translation of the Ordinary Form: Take this, all of you, and drink from it, for this is the chalice of my blood, the blood of the new and eternal covenant, (the mystery of faith) which will be poured out for you and for many for the forgiveness of sins. Do this in memory of me.
I’ve inserted the phrase “the mystery of faith” in the translation of the ordinary form to indicate where it comes in the extraordinary form. Note that the Latin texts of the ordinary and extraordinary forms are the same apart from the final sentence and the moving of the mysterium fidei, so that the translation is good for both forms up until the final sentence.
The ordinary form continues (rubrics in red) with the new translation and with one of the choices of acclamation:
Calicem ostendit populo, deponit super patenam, et genuflexus adorat. Deinde dicit:
The Priest shows the chalice to the people, places it on the corporal, and genuflects in adoration. Then the Priest says:
The mystery of faith.
Et populus prosequitur, acclamans:
Quotiescumque manducamus panem hunc et calicem bibimus, mortem tuam annuntiamus, Domine, donec venias.
And the people continue, acclaiming:
When we eat this Bread and drink this Cup, we proclaim your death, O Lord, until you come again.
The structure here is that the priest makes a proclamation “the mystery of faith” to which the people respond in acclamation (which is made clear by the rubric). There’s a clear sense of the people approving and applauding the proclamation of the priest. We might also note that “and the people continue” for “et populus prosequitur” is a bit weak; “prosequitur” better rendered with a sense of following or accompanying.
However, when we look at the old translation we find
Let us proclaim the mystery of faith:
Memorial acclamation of the people
When we eat this bread and drink this cup, we proclaim your death, Lord Jesus, until you come in glory.
The fragment “let us proclaim” is an invention of the old translation, not found in nor implied by the Latin original. We might also note that it is also somewhat inconsistent with the following rubric! The effect is to totally lose the proclamation-acclamation, priest-people, head of Christ-body of Christ structure. In the Latin and in the new translation, the priest has simply made the proclamation to which the faithful join in acclamation; in the old translation, the priest is inviting a joint proclamation with the faithful as though he had not already done it.
The general effect of the old translation here appears to be a weakening of the theology of the priest acting “in Persona Christi Capitis” (in the Person of Christ the Head) and therefore a weakening of the theology of the Church as the Mystical body of Christ. As such, the new translation is a welcome improvement.