Ban corporate ownership
I have not been able to work in commercial broadcasting since the station I worked for, WFUN-FM 95.5 Bethalto, IL, was sold from local ownership to Radio One in 1999. I would have been able to stay in commercial radio had there been more local ownership of local radio, and not this concentration on corporate ownership. I was not able to find work in commercial broadcasting in the St. Louis area; I was forced to give up looking in the spring of 2001. I lost my last broadcast job at a public radio station last July, after working there for nine years, due in part to the loss of the station's grants from the Corporation for Public Broadcasting. The best thing for radio (as well as the rest of the media) is a permanent ban on corporate ownership, and force only local and regional ownership of media.
And who decides who is a responsible broadcaster? Leave the airwaves alone. It's about the only freedom we have left anymore. Just because you don't like it doesn't mean it's garbage. Free speech is a privilege and people who would hold station owners liable for what broadcasters say are the same people who would order coffee someplace, spill it on themselves then sue the restaurant. Pettiness is far more divisive than broadcasters speaking their mind.
Why should owners of radio stations be protected from liability with respect to defamation? If you can't be a responsible broadcaster, maybe you shouldn't be in the broadcasting business. Corporate ownership leads to less diversity and localism and multiple ownership reduces competition. As neomaxcom points out, corporate ownership also makes radio owners less accountable for the garbage they broadcast. Local owners would be much more responsible and would probably be better at identifying good music.
Not only would this be unconstitutional, but incorporation is a key in separating liability for one's medium from one's own personal liability. Given the potential for defamation in the media - all media - the simple banning of corporate ownership would a bad idea.