To be fair to the op, someone HAS to say its a joke, for every time Blizzard unveils something that isnt a raid some people think it cant be true.
In the same vein, there will be people who will be mad that they didn´t take the time and resources used for this to make new [insert WoW content you prefer] for the game. Also, the doomsday prophets are always around to certify this announcement as the begining of the end.
Game looks pretty good. Much better than MTGO. Going after the CCG market is a smart move by Blizzard. They got into it a bit with WOW TCG, but they had a partner and it never gained the popularity that MTG has. Give than MTG is on their 20th anniversary, it's proven that it's here to stay for the long run. By releasing a computer version of a CCG (kinda like a mix between DotP and MTGO), they are going into a new market that relies on their expertise of release software products using an IP that everyone loves (Warcraft).