I have a good news and it’s coming via Canon :) The last couple of years Sony did lead the sensor world and Canon is struggling to keep up with Sony. But according to Stefan from CanonWatch Canon will now strike back with a new kind of sensor tech that will find his way in new cameras announced at Photokina. It’s good news for us because it means that Sony will have to answer soon too and we may see a sort of 3 layer Sony sensor sooner than expected.
At least at Low-ISO the 3 layer sensor from Sigma already shows an impressive performance (see here at MirrorlessRumors). But there are many issues on noise handling and so on. I am sure Sony has the knowledge to fix them and also to match if not beat any new Canon sensor tech.
All I can tell you know is that I heard about a 54 Full Frame Megapixel sensor from Sony (with 2460 focusing points (no joke!) and the focusing area covers 78% of the entire sensor). It was actually planed for a 2015 release but maybe Canon will make them change those plans…