It's unworkable. Ratings systems work because there's a list of criteria that, if a game ticks them off in any way, triggers a rating. Sexism isn't so black and white... a depiction of a stripper isn't inherently sexist, and a female business woman isn't necessarily an empowered depiction of that character. Then there's the sticky situation of satire and suchlike.
If you care about representation in games, fold that into the ratings criteria, don't add another stamp for games devs to ignore.
If you care about representation in games, fold that into the ratings criteria, don't add another stamp for games devs to ignore.