We see a trend across our customer deployments: more people are choosing Google as an OAuth provider over Facebook than ever before. Google will overtake Facebook this year. Customer preference used to be: 1) Email & Password 2) Facebook. Now it's: 1) Email & Password 2) Google and/or Facebook (tied for 2nd). Other companies in our space (Janrain in particular) have confirmed this.
I bet Facebook knows this and is trying to regain trust. The problem with what they are doing now is that more and more publishers and apps will probably just skip Facebook altogether. The primary reason Facebook was pushed so hard by so many for so long was because of the data provided. Take that away and people may move off the platform entirely.