The Church is not an American-style democracy. The music director has an area of competence that should be trusted. Ours has a degree in music performance with a minor in theology, plus 30+ years of experience. He should not bend and bow to individual clamorings for this taste and that. He should be trusted to be who he is.
In my experience I would have to look at this a different way. Some music directors are great. The one at my current parish is. But my experience of other MDs is that frequently they have 30+ years of espousing ideas about music that are 30+ years old. And I’m afraid, given what I’ve heard about the state of many universities 30 years ago, sometimes a minor in theology may be a hinderance rather than a help.
As for the congregation, I’m very surprised that nobody here has mentioned what I think is the primary reason people don’t complain about the H/H/S-type music. They are familiar with it. They listened to it as children or as young adults, and they like it because they know it, and they know it because music directors have been making everyone sing it for 30+ years. Because of this, congregations like it. I personally (although I do have training and education enough to know good music from bad) like several pieces of “bad” music simply because they have pleasant memories attached to them. Without musical training, I would know that I liked them, but not that they are bad. And I would probably resent anyone saying that they were bad.
The answer to this is to very SLOWLY change the mix between bad music (and bad theology) and good music (whether new or old). I’m not talking over a matter of months, but over at least a decade, preferably longer. Gradually lessen the use of the hymns that are merely bad musically, and more quickly lessen (and then terminate) the use of hymns that are bad theologically. Start the young people learning more good music, so when they are sentimental about hymns later in life, they will be good hymns (and incidentally may help those with no musical training have a better instinct for good music).
But this requires a music director that wants to eliminate bad music and bad theology from the music at Mass. I’m afraid that even with music directors who understand the difference, I haven’t seen a lot of willingness to do this.
BTW, St. Michael Hymnal is primarily traditional, but does have modern hymns as well. You can check it all out here:
stmichaelhymnal.com/NewEdition/Contents.aspx (Disclaimer: I have no connection with the publishers of the St. Michael Hymnal.

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–Jen
P.S. I like “God’s Blessing Sends Us Forth” but is anyone else a bit embarrassed when in verse 4 it talks about “this age of space?” How very… 1964. I think the Church does better when she tries to be timeless than when she tries to be timely.