It is implemented and working just disabled. It has no games recorded to predict from. The program is currently submitting games to my server to build up a game base to predict from but no one is using the program. My server only has 185 games recorded. The google guy who had the prediction feature had a game pool of 50k+ games I can enable it any time but there is no reason to enable it right now if there is going to be no accuracy to the prediction because there is no games to predict from.
With no one using the program the prediction feature will probably never be enabled. I have been to busy to play HearthStone myself recently but I wont be playing 50k+ games just so everyone else has a prediction feature.
The server is here
https://shadowfla.me/ and it displays how many games it has recorded.