I may be going against the grain here but I firmly believe it could ... and ... even should be a class!  Abso-friggin-lutely!

For me, and a group of people I know that do V.O. work ... we do more than just the voice part.  Whatever is needed.  Yet, even that is not just as simple as talk into a mic.  Move past that part, the part of being just a voice.  Great tone or a GREAT speaking voice is a huge asset and a solid start.  

However you hope the artist is malleable enough to listen to a producer/director/engineer in the control room while they themselves are in the booth.  Clock ticking.  Maybe the dollar signs too.  So now you hope the artist is able to hear or repeat the inflection the production staff is trying to get them to do or mimic.  The ability to do looping or dialogue sessions as in films.  Watch the footage and match your new lines to the onset ones.  The ability to give forty yards of odd grunts and groans.  The ability to now, record and edit your own V.O.’s and know what needs to be done.  From mic selection to pre-amp to sound treatment, DIY gorilla options, to high end counterparts.  What about software training to edit audio.  The ability to read a script and understand the call to action.  Connect with it in some way instead of having a great voice and just read it.  Then the ability deliver the same line multiple ways to give editors options.  How to fly in a word or line where needed so you don’t burn out your artist vocally by having them speak full unnecessary takes etc.

Lastly, just realizing that, it, in and of itself is a craft.  So YES ... Peace!

Stay healthy!  Stay safe!  Stay sane!