Android smartphone cameras have been criticized for a long time. No one really knows why Android devices keep having bad cameras overall (at least until more recently), but two main reasons for that could be that 1) Android OEM's just cared more about spec bullet lists, so it was more important to them to say they are the first with a 13MP camera, for example, instead of actually having a high quality camera, and 2) the stock Android camera software just wasn't very good, which made Android OEMs have cameras with poor performance, even if the hardware they put in there was great.
It could be either one of these reasons, or a combination of both. We know Google is at least working to fix the problem #2, but we'll probably have to wait at least until Android 4.5 or 5.0 (whichever version is next), until we see that released. That doesn't necessarily mean no Android OEM can release a great camera until then, though. I figure that companies like Samsung, who like to write a lot of stuff from scratch for their Android devices, have already optimized the software to fit their needs, which could be why Samsung has some of the better cameras around.
However, even if they have some of the best Android smartphone cameras, that doesn't necessarily mean their cameras are the best overall. Apple keeps proving to be tough competition to beat, even with lower resolution sensors, and Nokia has taken the fight to the extreme, preferring to have large bulges on their phones, if that means they can claim to have the "best smartphone cameras".
Samsung probably has ambitions to have the best cameras on the market, because they are going to merge both the wireless and the camera divisions into one, and getting those point and shoot camera engineers closer to the smartphone engineers. This way they can ensure their smartphone cameras can be as good as they can be, even if they don't intend to add OIS for a while. This is actually something Sony has done, too, and we can already start seeing that with the Xperia Z1, although we'll probably see more from that synergy next year.
"We will transplant the brand, sales networks, software competency and manufacturing competitiveness of the Wireless Business Division into the Camera Business Division, and integrate the technical know-how of the two business divisions into competency for differentiating our smartphones."
I've been hoping for a while that smartphones OEM's would either "steal" engineers from the big camera companies (Nikon, Canon, etc), or at least collaborate closely with them, so they can trickle down some DSLR technology and know-how into smartphones, so their smartphone cameras can become that much better.
Of course, Samsung and Sony have their own camera engineers, even though Samsung isn't one of the best at that level, but I'm mainly talking about companies like HTC, Motorola, LG and others, who could really use the expertise of the Nikon/Canon engineers. It could also prove to make a lot of money for those two companies, through licensing, as they try to adapt to a world that doesn't really need more than a smartphone to take photos. It would be win-win for everyone if smartphone OEM's and camera makers started working together more closely.