Some interesting comments by Peter Planyavsky on the possibilities of writing good music for the post-Vatican-II church:
"You are not to write a 'pretty' or 'interesting' piece which 'can also be performed in the liturgy,' but rather, you should truly compose above all for liturgical use – with all the consequences. ...
"All right, let's talk about the Responsorial Psalm. Whoever has in mind an awful, primitive, monotonous little ditty should please think again. Nowhere is it demanded that it may not be elaborate, dignified, polyphonic, and original. Fundamentally the structure of solo psalmody should be maintained, but there is much more that can be done with it. The same is true for the Alleluia verse. Further: the manifold possibilities of alternation by stanza between choir and congregation are not yet exhausted. ...
"So far, none of the church music alarmists has been able to explain to me how the task of setting the 150 psalms (that is 77 pages), compared to the Ordinary (that is two pages), represents a limitation. ...
"I resist any fundamental charge of a deficit for which the liturgy of the Second Vatican Council would be guilty. The foundational and functionally coherent involvement of the congregation (and that does not mean always, everywhere, constantly, and primitively!) is not a bureaucratic spawn of a few music-hating liturgists. Rather, it was a radical innovation of our [twentieth] century that was awaited with longing all across Europe and in many places already practiced illegally by anticipation. Again, I wish to emphasize, the effects for sacred msuic have been predominantly positive and inspiring to the imagination."
(Peter Planyavsky, "Komponieren, aber für die heutige katholische Liturgie" ("Compose, But for the Current Catholic Liturgy"), Singende Kirche, 1988f. English translations from "Sacred music and liturgical reform: treasures and transformations" by Anthony Ruff (2007).)