Thing is, it doesn't have to be a good one or anything, just add some legal expectation that they provide some level of constructive criticism. This would disincentivize shady hiring practices, allow job seekers to actually do something about meaningless obstacles to employment, it also would strongly discourage lazy practices like “always accepting applications”, and leaving listings up that are long since expired.
It would clarify and clean up a job market that's a trainwreck of spam and misinformation.