Your words were still with me at Mass this morning (a N.O. liturgy -- not my customary worship -- using Eucharistic Prayer #1). In adoring the Eucharistic Elements immediately after the repetition of the words of institution, celebrant and congregation alike signify the belief that Christ is really present on that altar. It seems that an epiclesis after this point would be redundant so far as "accomplishing" transubstantiation is concerned. In my unlearned layman's view, the logic of a "wishful" epiclesis in advance of the words of institution seems more persuasive than to pray for the ratification of something the Church teaches has already taken place. I believe the Greeks do not share the Roman interest in defining the precise moment at which the change occurs, or whether it can be said to happen in a moment at all. But we Latins make a point of adoring the Blessed Sacrament at the elevation, and that seems hard to get around.
Happy New Year, btw.