He is the image of the invisible God, the firstborn of all creation. For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him. And he is before all things, and in him all things hold together. And he is the head of the body, the church. He is the beginning, the firstborn from the dead, that in everything he might be preeminent. For in him all the fullness of God was pleased to dwell, and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.
Not that I'm primed at just this moment to discuss the implications of this passage at any great length, but ask yourself what an implication of this text would inevitably be. If God was pleased to reconcile to Himself all things through Christ, whether on earth or in heaven, making peace by the blood of Jesus' cross, then why wouldn't this reconciliation include all musical styles?
While this obersation won't settle all questions as to what is liturgically appropriate this does settle the question of whether or not any musical style is reconciled to God the Father in and through Christ. There is no music that is inherently "robustly trinitarian" (i.e. post-Renaissance tonal music in the West) or inherently pagan as music goes. There may be texts extolling pagan deities or pagan ethics or things like that but the music, as music, is still part of the "all things" that would be within the work of reconciliation accomplished by Christ.
If this seems like an observation that is mundane or irrelevant consider this in light of the worship wars that have been brewing and will continue to brew until Jesus comes back. If in Christ there is no Jew or Greek, male or female, and slave or free then there is no longer a high and low, an East and West, or a pop and art boundary that must inherently accrue within the fellowship of God's people. There is no boundary between circumcised and uncircumcised any longer, for both are reconciled to God through Christ and to each other through the removal of the barrier of the Law (read Torah, read whatever boundaries you insist on keeping where ever you might want them to be). Does this mean any and all music is a-okay in a liturgical setting?
Well, not necessarily, but the metric does not necessarily depend on just one metric of "musical excellence" but of service to the body of Christ. Musicians playing or singing to the lowest common denominator for certain types of music is not a matter of forsaking musical excellence as such but an act of loving service to, well, let's not sugar-coat this too much, the musically illiterate. :) In personal terms, just because I can play fugues on solo guitar or like to play works by Toru Takemitsu now and then doesn't mean I won't be happy to strum a series of open chords in the church orchestra if that will be more beneficial to a congregation.
And that's about all I feel like writing about on that for the moment.