This debate of speculation is adorable, but less than a month we will find it all out. Until then just enjoy your hearthstone beta, and level alts and gear them up in the timeless isle : ).
P.s. Heroes of the storm seems logical as the new Blizzard DotA and The Dark Below is being kept secret for a very big reason. It's Blizzards cash cow and they need a big success this time around to earn some of that Vevendi money.