Of all the recurring topics Blizzard faces on the forums, player housing might be the most recurring-- since many other MMOs are more than happy to offer customizable spaces to their players in the game world, a lot of players continually ask Blizzard why they haven't. And the answer is only partially unclear: as you might expect, Blizzard isn't interested in doing something if they can't do it better than everyone else, and at this point they just haven't figured out exactly how to do it their own polished way.
But in its current iteration on the forums, there's a bit of a surprise: many players don't care about player housing in the first place. As Drysc says, "support is not widespread," and considering everything that Blizzard is working on, there's no way they're going to jump into something as big as player housing without having a large portion of the player base behind them.
Then again, players are always in favor of customizing their characters-- look at the hairstyles coming up in the next expansion. If Blizzard can figure out a way to give players a customizable space that was both great looking and easy to customize-- something players could show off to each other and store achievements in-- then there's no doubt that most players would probably jump at the chance.