Well, not so much the cantors themselves, but their roles.
In one of the best articles yet since I've started blogging a couple of years ago, Michael Lawrence over at the NLM proposes a reformed role for cantors.
In this writer's experience, the cantor is usually responsible for the following: a) leading the hymns--which typically replace the Propers--and the Ordinary, much of which, if in a responsorial format (particularly contemporary hymns and settings of the Gloria), requires a great deal of solo singing on the part of the cantor; b) singing the Responsorial Psalm and the Alleluia; c) encouraging the congregation to sing via bodily gestures; and d) announcing the hymns. In many places, the cantor must do all of this from a podium or an "ambo" (sic)* which is located in the sanctuary, or in some area in the front of the church that is rarely conducive to working with the organist. In addition, the cantor usually makes use of a microphone for every word that is sung.
At Holy Ghost, C and D are omitted from a cantor's duties, thankfully. C has never happened, and I stopped the practice of D last Spring. My practice for A and B is to play the people's parts fairly loud (with a few exceptions, namely something that might not be meant to be played all that loud to begin with), toning down only for those parts that were meant strictly for a cantor (namely intonation and verses to the Psalm and the Alleluia). Most of the hymnody we use is through-composed, with the exception of Communion, where I often program something a little more on the responsorial side.
At one time, it was common for lectors to double as "commentators" and and take on the role of announcing (until the misconceived role of cantor came to practice, at least). Some of the announcements you'd hear are often hilariously dumb, about as dumb as one would put the average congregant out to be. Here's an example of a variety show host at work (this actually happened at the parish I grew up in as a teen):
(Before Mass begins):
Good morning. I'm Bill L., my partner is my wife Clara.
Our Ministers of the Eucharist (note wrong term) are Bob L. and Jim T.
Our Acolytes are Chris and Jim T.
Our Minister of music is Jerry A., assisted by our soloist, Pauline M.
Our Celebrant is Father Joe. Let us stand and greet him as we sing "Hail, Holy Queen", number 307 in your song books.
(At the Offertory):
As our ushers collect our thank-offerings and present them to the altar, let us sing "Kumbaya", number 42 in your small missalettes.
I've seen parishes where cantors are trained to pull something similar. Michael states in his post: It seems plausible, too, that many of them are only following orders from someone in authority over them.
He's absolutely right. In some cases, that authority is the music director. In a good amount of cases, that authority is the pastor, or a curate that the pastor has put in charge of liturgy, or that highly paid "liturgist", hired to "custom create" the liturgy. I've said it before: hire me as your liturgist and I'll do two things - 1) train all involved to "do the red and say the black", and 2) subsequently eliminate my own position. Because once you've successfully done step 1, there is no need for a lay liturgist. (OK, so I added some liturgist reform too!)
Back to cantoring. Michael proposes this idea (which is a very good one, I might add):
There are instances, however, in which cantors might lead the hymns or the Ordinary profitably. Generally this would be in the absence of the organ. Even still, the cantor should not dominate the whole piece, but should rather get the music started by singing the first few notes or the first line of the song. The same applies in much of the Gregorian chant repertoire, where, traditionally, the music is begun by a cantor or a smaller group of singers. For our convenience, let us file both of these situations under the category of "incipits."
BAM! Speaking of which? How many parishes have music directors who know what the Graduale Romanum or Gregorian Missal is for? Ever see that little asterisk (*) after the first word or two in a proper, or after the first bar of the alleluia? That's when the "cantor" part of it ends. We should do the same with hymn singing, and even the Ordinary.
Since I'm leaving in a little bit to take my daughter to her regularly scheduled eye doc's appointment, I'll let you read the entire post by Michael Lawrence. Excellent reading!