Personally, for the next best thing for cameras, i suggest Nokia 'steal' back HTC's idea. To limit the thickness of camera, instead of 41MP, put in three 25 MP stacked sensors (HTC's One has three 4MP stacked sensors.), then combine with OIS. If the sensor is 25MP, and they maintain the size of the pixels in microns, that means the sensor dont have to be too big, maybe 1/1.6, instead of 1/1.2 on 808PV. Honestly speaking, im not fond of the idea by HTC to have larger size of pixels to capture more light - for that, let a large sensor or OIS or both do the job. Since they had to keep their phones slim they kept the sensor size at 1/3. Yes, if pixels are small u get more noise, and that's what oversampling will solve it to some extent.

And now let's look at the 41MP on 808PV - 5MP photos will have around 7-8 times oversampling; 8MP around 4-5 times oversampling.

If use three 25 MP stacked sensors, that means a 8MP shot will have 3X oversampling from the stacked sensors, and another 3X oversampling digitally due to the large sensor. That makes a 8MP shot having 6X oversampling, instead of just 4-5 times in the 808 PureView. If they want to limit the amount of lossless zoom, then limit the digital zoom maximum to 3X only, and even zoomed in image have another 3X oversampling from the stacked sensors. Best of both worlds.

For 5 MP shots, 5X oversampling the stacked sensor and another 5X digitally gives you 10X of oversampling, or a 5X lossless digital zoom with another 5X of oversampling involved. Zoomed in images have both details and also less noise.

No idea if im doing my maths right, but i think you guys get my idea.

Low light performance, just slip in OIS along - provided they can apply it to a larger lens and sensor, no need Xenon flash since it is too bulky. If all i mentioned theoretically is possible, we might see an even more godly camera phone compared to 808 due to more oversampling despite lesser megapixel count. For me i would personally prefer oversampling technology over OIS, but having both is awesome. Noise is difficult to get rid off (risk of losing details in photos) if excessive photoshopping, oversampling can get rid of noise and preserve detail. The phone may still be thick, but if used with aluminium material i believe it can be a lot slimmer than 808 PureView since Xenon flash is not used.

But seriously, even if my theory above works, a really powerful graphics unit and processor is needed, something like Snapdragon 600 or 800.