I am sure that the A7rII is a very good and capable camera and I cannot even say if I would love to hold one and be able to connect to it, as I so far had no chance to get my hands on one.
But finally for me the system is what counts and what I absolutely hate is mounting third party lenses via adapters, even if it is mounting an A-mount lens via an adapter to the FE mount. Again, that's just me!
Thus the consequence for folks like me is to wait till the FE system gets all the choices I need and require before it can replace any other system which gives that advantage. And so far Nikon - while sure they have been pretty lazy in following the bandwagon - at least still have their big Nikkor system advantage (as Canon does). So I - and I am only talking about me again - can find the lens I want in that system pretty easily, while I cannot in many cases in the FE system.
Now if I restrict myself only to the available FE lens lineup, which seems to contain some very excellent marvels, then I might easily be able to get the A7rII with that native glass, add it to my camera collection and be a very happy camper. And that might happen sooner than later.