All the talk lately has centered on this article in Wired magazine, by Tracey John, who interviewed Blizzard COO Paul Sams at Blizzcon.  In it, Sams lays out the fact that the “secret MMO” that Blizzard is working on:

…Is going to be significantly differentiated enough. Such that, you’re not going to feel like they’re one in the same resulting in that you have to pick or choose.

Strangely, though, Sams indicates that Blizzard is still committed to its’ “new expasion to WoW every year policy.”  He even says:

With each expansion we’ve definitely shortened the window. So we’re going to keep trying to do that. I hope and pray we’ll get to 12 months.

The first expansion was released a bit over two years after the game launched.  The second expansion was released 22 months after the first.  The third looks to be released… about 20 months after the second.  So Blizzard is on pace to get the window shortened to 12 months… with their 7th expansion.

In mid-2015.