The revenue of Hearthstone on a yearly basis will be bigger than all these games combined.
So nope. WoW will stay the huge money maker along with WoW's Hearthstone...
Come back when all of these games will make 300 million dollars combined... It won't happen.
The projected revenue for WoW + HS is expected to be around 1.2 billion dollars per ... year as of 2014.
And HS will simply act as a catalysator for WoW's next expansion.
With Blizzard's All Stars added too (or just put in the latsest name for it)... playing Warcraft will be MUCH more than playing WoW.
The franchize is just starting to spread really.