@russtrotter We don't want you to feel like you have to go visit it forever. It's a MoP feature. It will still be there for you though.- Greg Street (@Ghostcrawler) July 13, 2013
So, it seems like the good news is that the ranch definitely won't be gone for good. It will remain on Pandaria, in its peaceful setting,for you to visit whenever you see fit, grow some herbs, watch the virmen and the birds, kill a weed, or just shoot the breeze with your pets. However, it doesn't sound like it will continue to be updated in the new expansion.
What does this mean for the farm's success? Did it perform how the devs had hoped? Did it kill herbing? Were players too reliant on it? It would certainly be interesting to see whether this means an enhanced farm, or even something more akin to the much-desired player housing might appear with 6.0. It is also possible, of course, that the farm might go the way of other features that have been left for dust, and never reappear.