If they don't want to take the time to read why something has achieved a certain letter grade, then that's their fault as parents. As it stands now non-descriptive letter grades allow censors to play games; the system becomes either a sales ploy, or a way for censors to unnecessarily influence a movie's ability to perform in whatever demographic it was made for. Descriptive ratings change the psychology of the thing. 

Drastic and unrealistic would be re-adapting children to be more receptive to movie markets. Changing the way movies are rated is hardly drastic. PG-13 was created for the exact reason you are suggesting PG-15, and... [url=https://www.youtube.com/watch?v=O-NeJRrgoTY]this happened[/url].