I was looking for the exact same thing! I really don't like the pop-ups which are always when I don't have time for them, so this feature was something I was really looking forward to. (Who even writes a review when being asked for it like this...?)
From what I'm reading on the web right now it seems that the button is cancelled in favor of asking for a review for a maximum of three times per year per app. So that doesn't help with 85 app's currently installed...
Probably because developers wanted to keep the option, but I'm still disappointed that we continue to be nagged with these app review requests
.