The hermeneutics of fittingness: traditional Requiem Mass vs. new 'Mass of Resurrection'

A writer recently wrote asking: "How about a thread on the hermeneutical fittingness of the traditional Requiem Mass, versus the new 'Mass of Resurrection'?" This is something I hadn't considered before, having never yet attended a Catholic funeral Mass. I have heard some accounts, however, of the differences between the pre- and post-Vatican II rites. The writer went on to add:

I attended a funeral yesterday of a Catholic man who committed suicide, leaving behind a young wife and four small children. I expected, but was still deeply disturbed by, the constant refrain throughout the Mass that we can pretty much have certainty that this man is in Heaven. The rite itself papers over the obvious problem--this man died in the very act of committing several extremely grave sins without any chance for sacramental confession. Is it really good that the Church bids her priests verbalize assurances for things of which they really have no way of being sure?

I would think that the acknowledgment in the traditional Rite of the sting of death, along with its emphasis on the divine mercy would have been more appropriate than blithe assurances of resurrection, especially under these circumstances.

I remember thinking to myself, "Whatever became of the Dies Irae within Catholic hymnody?" The Dies Irae ("Day of Wrath"), the famous 13th-century Latin trochaic hymn describing the day of judgment, with the last trumpet summoning souls before the tribunal of God, has been dismissed as too dark and judgmental by the Barney and Friends company of contemporary liturgical commissioners. But Christians of all stripes have traditionally written of this hymn such things as this: "Among gems it is the diamond," "solitary in its excellence," "the acknowledged masterpiece of Latin poetry and the most sublime of all uninspired hymns" (Catholic Encyclopedia). In the current Latin Breviary, it is suggested for use in the Liturgy of the Hours during the last week of Ordinary Time. I think I remember the editor of Adoremus Bulletin in a recent issue assuring a reader that there is nothing in the rubrics of the Novus Ordo that would proscribe the use of the Dies Irae. But this is hardly enough. There is nothing that would proscribe ad orientem Masses, Gregorian chant, or the restoration of Tabernacles to the center axis on or behind the Altar either -- and there actually is something (Redemptionis Sacramentum) that proscribes the ordinary use of unnecessary Extraordinary Ministers of Holy Communion. But how has that kept anything from changing?

The question before us, however, concerns not the Dies Irae but the traditional Requiem Mass as such versus the new "Mass of Resurrection." The question pertains to these Masses as discrete wholes, as well as to all their parts. Does one express more fittingly than the other what is proper to Catholic theology and sentiment, and, if so, why?