This was seen by some as "Fairness Doctrine 2.0." Left and Right alike knew what a chilling effect this would have on newsrooms. The study techniques involved were incredibly invasive, researching specific newsroom content. Clearly the outcry over this has the Commission backing off; but it likely wouldn't have passed constitutional muster and the FCC really doesn't want one of its policies losing at the Supreme Court.
And it would have gotten there because most media companies would have refused to comply.