It would be suicide to do it now. What about in some months, when everybody has forgot about the debate and most of the users are constantly logged on google+ and use the feature as their standard search? Again, Facebook does it all the time and manages to pull it off on a regular basis.
I can't think of an example of Facebook taking away a preference setting that users have adopted. Even Facebook doesn't take away controls it has freely given. It would be one thing to take away the toggle button. That might happen, and it would suck if it did. But to go in and pull out a user setting that people are using, that would be astonishing.
