(As regards comments, see the first part of this)
Why this Gadarene preoccupation, in the 1960s, with epicleses asking the Spirit to be sent to change Bread into Body? The answer is embarrassingly simple. Pretty well all rites except the Roman had an epiclesis. Therefore it must be 'Primitive'. Therefore it was desireable. The alternative possibility, that Rome lacked an epiclesis because it was older than those other rites, occurred to very few. So, for a hundred years or more, the question had been (not why did the other rites add an epiclesis, but) Whatever Happened to the Roman Epiclesis ... deemed to have existed originally but, for some mysterious reason, to have gone missing. Readers who still have on their shelves The Mass by Adrian Fortescue can still find page after page describing the ingenious pursuits, by entire generations of clever and erudite men, of this particular invisible (well, to be frank, mythical) fox. The conviction was bolstered by an inclination to believe that all the existing rites of Christendom must have descended from an Original Liturgy which, at least in its dominant features, was fairly uniform, and could therefore, in principle, be reconstructed from a comparison of existing liturgies. This assumption, as the pendulum swings, is currently highly unfashionable; an Anglican liturgist called Paul Bradshaw has spent most of his life rebutting it.
But why should we not just add the epiclesis to the Roman Rite anyway? Would it not be an Enrichment? There is surely no real harm ...
I began the first part of this enquiry by printing an Eastern epiclesis of the Spirit; and the nearest equivalent which the Roman Rite possesses. Put simply, the East says Send the Spirit so that He may change bread into Christ's Body. While Rome says Accept our Offering so that it may become Christ's Body. In other words, awed by the great mystery of this Change, the East is convinced that the most powerful Force that there is - God the Holy Spirit - must be responsible, and needs to be invoked. Rome, in her humdrum way, has carried on with the earlier Christian belief that the simple acceptance by the Father of the Church's Oblation will mean that bread will be changed (in accordance with the definitive and prescriptive Word of the Lord at His Supper) into His Body. Accordingly, Rome has felt the need to be confident that the Father really has accepted the Oblation, while the East has been concerned to ensure that the Father really has sent the Holy Spirit ... at least, that is the conclusion I draw from the emphases within each respective Petition, one Occidental and the other Oriental. So, in the West, as the sentence ends in which this Prayer for Acceptance is made, the bell is rung and the Priest is lifting up the Lord's Body for Adoration. In the East, solemnity attends the Prayer for the Spirit.