the 6Dmk2 would be built close to 5D3 while retaining its small size and multi-directional dial (whatever you call it).
The problem with the 6D is that it was apparently conceived when the 5DIII specs were frozen.
So, not much breathing room for Canon to give it proper specs.
Going forward, I'm not sure that the 6DII will be build close to the 5DIII.
I do expect, though, that the 6DII will be properly differentiated from the 5DIV - without having to be crippled.
We'll see what happens.
Body size (form factor in general) will surely remain a key differentiator between the two.