For Lutheran Christians there should be no question at all. The catholic faith, as most of us confessed this morning, is that we worship the Trinity in Unity and the Unity in Trinity without either confusing the Persons or dividing the Substance; and to faithfully confess the incarnation of our Lord Jesus Christ, who is God of the substance of His Father before the ages and man of the substance of His mother, perfect God and perfect man, of a reasonable soul and human flesh subsisting.
It is a good question, then, to ask of ourselves: is our worship explicitly Trinitarian and confessing the Incarnation? Is it catholic?
One is struck right away by the rich way in which the Lutheran liturgy confesses the Trinity! From the opening invocation, the conclusion of the absolution, the Gloria Patri in the Introit, the three-fold (or nine-fold) Kyrie, the Trinitarian shape of the Gloria in Excelsis, the triple Alleluia before the Gospel, the three articles of the Nicene Creed, on to the proper preface with its "one God, one Lord, and in the confession of the only true God we worship the Trinity in person and unity in substance of majesty coequal," then the triple Sanctus (and the tripling of "blessed is he" and "hosanna"), the Gloria Patri at the end of Nunc Dimittis and the Aaronic benediction. Not to mention the termination of the collects: "through Jesus Christ, our Lord, who lives and reigns with You and the Holy Spirit, one God, now and forever."
From start to finish, the Lutheran liturgy is profoundly Trinitarian, a worshipping of the Three Persons in Unity and the Unity in Three Persons. It's worthwhile to put that liturgy into the balance of the scales and weigh its proposed replacements for Trinitarian glorification. How well do they do? I think it would be most revealing.
For me, I'm delighted to be a catholic Christian who worships Father, Son, and Holy Spirit and who confesses the incarnation of our Lord Jesus Christ in the Divine Service.