"Singing the Mass", not "singing at Mass" - 2
Included in the second tier of importance of things to be sung at Mass are the Entrance Procession, Gloria, Psalm, Communion Procession and post-Communion. The Gloria is the great hymn of praise of the Triune God and, personally, I am a little disappointed that it only makes the second tier. That said, it is still considered more important than singing during the Preparation of the Gifts (Offertory) and the Recessional - and it is a daring parish liturgist that would miss out those! There would be revolts in the pews!! Not so long ago, before the New (English) Translation of the Missal, it was permissible to sing a setting of the Gloria (and, indeed, all the Mass parts) that paraphrased what was actually in the Missal; the Peruvian Gloria, for example, proved popular with many. That is no longer the case, as I found out myself when I submitted my first Mass setting (High Peak Mass) for permission to be used outside of my own parish; permission was at first withheld...