By now, many clergy and wedding musicians are familiar with the expanded prescriptions of the Gloria, including its provision in ritual Masses, including weddings, and even on a Lent or Advent weekday.
I had a wedding Mass this past weekend in which the presider followed the 1970 Order of Marriage and included a penitential rite. We didn’t prepare a Gloria for singing. But I’m wondering about that next wedding Mass on my schedule.
Let me offer up the purple chair for you with the following questions:
Will you sing or say the Gloria?
If you sing, which setting?
Is the Missal’s Gloria XV really suitable for a festive occasion like a wedding (let alone Christmastime or the Fifty Days)? And if you anticipate people won’t sing it anyway, why not take up the option of a performance piece, even another chant like Gloria VIII?
What’s your opinion on the MR3’s expanded use of the Gloria?
Catholic Sensibility 
Well, inclusion of the Gloria has the connotation of a feast (or solemnity). Is not the celebration of Matrimony a festal occasion? I hope so as a typical matter. And the Gloria begs to be sung: it is a hymn, after all. As the introit chant/song is typically omitted in nuptial Masses in favor of an instrumental processional, it would be a good way to conclude the introductory rite.
That said, for practical reasons, there will likely be non-Catholics and lightly churched Catholics present who won’t sing or even say much of anything; I would not plan music choices with them as the focus.
I’d recommend settings the revised version by WLP of Proulx’s Missa Simplex, the recurring motifs of which make it easy to pick up on the first try, but without monotony:
Wow, how’d I miss this memo? Great news! One more liturgical obligation for which the forlorn music provider will fulfil the moment while the audience, whether RC’s or not, will occupy their thoughts with anything, anything other than what’s going on a few feet from where they’ve parked their derrieres. And of course, the forlorn musician will endure the passing notes and time immersed in kinetic motion while s/he ponders why the faster s/he plays and sings, alone, the slower time passes. The ineffable wisdom….