Now, as far as computer enhanced voices go, I doubt that any CD or TV show or movie is released without some sort of electronic manipulation of the voices or music or some other audio component taking place.
Electronic manipulation is commonplace and they are acceptable. It's been like that since the 60's and it's like that today, and will be so in the future.
The problem is that more and more people don't know how to sing and studios/labels take them anyway due to their looks alone.
With the advent of automatic pitch correction scheme, too many so-called singer are becoming lazier every day and becoming much too dependent with the technology.
I've experienced too many top-40 singers (I can't disclose their name due to NDA with the artists and labels involved) who can't sing to save their lifes. So far, I've been spending up to 200 hours per song fixing their vocals.
No, it's not like adding reverb, echo, delay. Sometimes I have to change the entire passage because (picture the following as a melodic line) they sing "C-E-F" when they are supposed to be singing "C-D-G".
Yeah, from the digital artifacts I hear of Hillary's recordings, she doesn't sound like she needed 200 hours of fixing for each song, but she DOES sound like she had been fixed at least 25 hours for each song.
Of course, singers like Diana Krall, Michal Buble, Tony Bennett, require 0 hour of pitch correction. So do Gloria Estefan, Usher, Michael Bolton and Kylie Minogue.