I think the controversy regarding the translation "pro multis" distracts from another very grave concern about possible invalidating effects of the N.O.M. canon or at least the invalidating intention behind the reforms.  

From "A Short Critical Study of the Novus Ordo New Order of Mass":

4. THE FORMULAS FOR THE CONSECRATION

The old formula for the Consecration was a sacramental formula, properly speaking, and not merely a narrative. This was shown above by three things:

a. the text employed

The Scripture text was not used word-for-word as the formula for the Consecration in the old missal. St. Paul's expression, the Mystery of Faith, was inserted into the text as an immediate expression of the priest's faith in the mystery which the Church makes real through the hierarchical priesthood.

b. typography & punctuation

In the old missal, a period and a new paragraph separated the words, "Take ye all of this and eat" from the words of the sacramental form, "This is My Body." The period and the new paragraph marked the passage from a merely narrative mode to a sacramental and affirmative mode which is proper to a true sacramental action.

The words of Consecration in the Roman Missal, moreover, were printed in larger type in the center of the page. Often a different color ink was used.

All these things clearly detached the words from a merely historical context, and combined to give the formula of Consecration a proper and autonomous value.

c. the Anamnesis

The Roman Missal added the words "As often as ye shall do these things, ye shall do them in memory of Me" after the formula of Consecration.

This formula referred not merely to remembering Christ or a past event, but to Christ acting in the here and now. It was an invitation to recall not merely His Person or the Last Supper, but to do what He did in the way that He did it.

In the Novus Ordo, the words of St. Paul, "Do this in memory of Me," will now replace the old formula and be daily proclaimed in the vernacular everywhere. This will inevitably cause hearers to concentrate on the remembrance of Christ as the end of the Eucharistic action, rather than as its beginning. The idea of commemoration will thus soon replace the idea of the Mass as a sacramental action.26

The General Instruction emphasizes the narrative mode further when it describes the Consecration as the Institution Narrative27 and when it adds that, "in fulfillment of the command received from Christ... the Church keeps his memorial." 28

All this, in short, changes the modus significandi of the words of Consecration, how they show forth the sacramental action taking place. The priest now pronounces the formulas for Consecration as part of an historical narrative, rather than as Christ's representative issuing the affirmative judgment "This is My Body." 29

Furthermore, the people's Memorial Acclamation which immediately follows the Consecration, "Your holy death, we proclaim, O Lord...until you come" introduces the same ambiguity about the Real Presence under the guise of an allusion to the Last Judgment. Without so much as a pause, the people proclaim their expectation of Christ at the end of time, just at the moment when He is substantially present on the altar, as if Christ's real coming will occur only at the end of time, rather than there on the altar itself.

The second optional Memorial Acclamation brings this out even more strongly:

"When we eat this bread and drink this cup, we proclaim your death, Lord Jesus, until you come in glory."

The juxtaposition of entirely different realities, immolation and eating, the Real Presence and Christ's Second Coming, brings ambiguity to a new height.

And as St. Thomas observes in ST III, Q. 78, A. 6:

On the contrary, Directly the words are uttered for consecrating the bread, the consecrated host is shown to the people to be adored, which would not be done if Christ's body were not there, for that would be an act of idolatry. Therefore the consecrating words of the bread produce their effect before. the words are spoken for consecrating the wine.

I answer that, Some of the earlier doctors said that these two forms, namely, for consecrating the bread and the wine, await each other's action, so that the first does not produce its effect until the second be uttered.

But this cannot stand, because, as stated above (5, ad 3), for the truth of this phrase, "This is My body," wherein the verb is in the present tense, it is required for the thing signified to be present simultaneously in time with the signification of the expression used; otherwise, if the thing signified had to be awaited for afterwards, a verb of the future tense would be employed, and not one of the present tense, so that we should not say, "This is My body," but "This will be My body." But the signification of this speech is complete directly those words are spoken. And therefore the thing signified must be present instantaneously, and such is the effect of this sacrament; otherwise it would not be a true speech. Moreover, this opinion is against the rite of the Church, which forthwith adores the body of Christ after the words are uttered.

Msgr. McCarthy comments:

Certainly, the effective force of the first words carries over into the following words, but they do not have the same effective force, not only because they do not declare the transubstantiation, but also because they are in the future tense ("which will be poured out"), and the future tense as such does not produce or participate in an immediate effect.

Now, if it stands to reason that there had been intended a transformation of the consecration formula into merely an historical narrative, a mere rememberance of the past and a reference to an eschatalogical reality in the future, it must be that the words are not effective of a present reality.  The words become radically false and could not produce an immediate effect.