The main reason why the choir directors I know are not really happy is because the new translation music isn’t very pretty.
I have yet to hear any of it that I find pretty. It’s disjointed and the melodies are rather stilted. It sounds like someone hobbled the words of the new liturgy translation to any old notes, just to be able to put something out on paper and get it out there.
Another reason why choir directors are not thrilled is because in the Catholic Church, there are few venues to teach their parishioners anything new. Many parishes have few good cantors who can sing on pitch in a strong voice and are also comfortable teaching others.
In our parish, anytime something new is sung, the music director does the teaching right before Mass, which means that there are not very many present in the nave yet, and those who are there often don’t participate, as they are (1) praying (2) meditating on the Blessed Sacrament, or (3) dealing with small children and getting settled. IT’s very, very awkward, and IMO, disruptive, but that’s really the only option for the music director.
It’s just hard, because you can’t “teach” music during the actual liturgy of the Mass. That would be incorrect.
Also, the music directors know, with a sinking feeling, that they will receive a boatload of complaints from parishioners for the first few months and longer of the “new” translation, and this is really discouraging. Perhaps they should set up “complaint boxes” and set them next to the choir loft, and just point to these boxes whenever an angry parishioner approaches them.