[Brightcolours]

BSI sensor removes most of the issues with wide-angle Leica M glass that were common with previous digital cameras

 

http://www.stevehuffphoto.com/2015/08/04...o-far-wow/

The discolouration issues have to do with microlens position/structure, not with whether the sensor  is backside illuminated or not. See NEX-5 and NEX 5R.

 

The issue of sensor glass (and astigmatism resulting from it) won't be fixed.

 

Sidetracking, the  Canon AF compatibility is very hit and miss. Some lenses are impossible to use with any confidence, like the Canon EF 100mm f2.8 L IS USM Macro. 

A7R II users also report a big issue with manual focus magnification in the viewfinder (akin to the Nikon D800 live view magnification problem).