Google Voice for Hangouts, What is the hold up

I use Google Voice for my primary number, and like many HATE the Google Voice app. Ever since Google Hangouts for iOS got VOIP calling, and along with the unoffical "offical" announcement that Google Voice was coming to hangouts. I am begging for the feature to be rolled into the app.

Along with the fact that iOS just got a big update, anyone feel like it will come sooner rather than later?