Of course this depends on who is making the camera, but I would generalize and say that megapixel count is largely irrelevant with mobile phones. Just from my own experience with my LG Optimus G, it has a 13 megapixel camera. And whether I select the saved image quality to be 5mp or 13mp, I can't see a lick of quality difference when I view photos on a large screen. Sure, this also has to do with how good the compression being used is.
Optics are king. Maybe Apple is at a point where the MP count is actually limiting their photos...but I am skeptical...
Regardless, it's the trend to pack more pixels in everywhere. Whether you need them, or use them, or not.