I'm not sure that this megapixel war would extend further than 41 MP anytime soon...
so for me, 50 MP sensor (not 50 MP image from several stitched 13 MP pictures which is what the Oppo Find 7 does) is unlikely
8K video?
damn, even 4K is way overkill for a mobile phone
AFAIK, there is no 8K screen used in the world at this moment
the camera tech possibilities have been discussed thoroughly in this thread...
as for me now, I would prefer a 41 MP with a 1" sensor, an even more advanced OIS, ZEISS lens or Canon Liquid Lens, and adjustable aperture
for the processing part, I'd prefer Qualcomm Snapdragon 805, 2 GB RAM, and a fast 64 GB internal memory (expandable or not, I don't really care)