First problem - most church "musicians" aren't serious. They do it because "they like to sing." Just getting some people to do simple warm-ups is incredibly difficult. I've actually heard people ask why they are wasting time with warm-ups.
Church organists struggling with the works of Bach and singers attempting to master the intervals and nuance of Gregorian chant face very similar battles.
Most Bach isn't really suitable for anything other than a postlude. Vocal Bach takes a specific sort of voice, too. There are other composers who's work is far more challenging.
Maybe it's just years of hearing it, but chant nuance is nothing in comparison to trying to master Mozart line and phrasing. And Gregorian is much easier than some of the other forms of chant.
Musicians need to rethink their place in liturgy and begin to think of the sounds they create as part of the structure of the Mass and not purely additive. That means acquiring chant books from Solesmes and spending time every week and every day on familiarizing oneself with Catholic tradition.
It also need to be explained that Mass is not an alternative to being a member of a rock band.
Sacred music requires humility and a willingness to go beyond pleasing ourselves and our immediate audiences alone. Sacred music requires sacrifice and loving service to the God the Father and his Church.
Yes. When you can't get people to join choirs, though, because they don't want to commit themselves to a weekly commitment....
I cajole 'em - my husband "persuades" 'em . . . < g >