The way I see things, which is not necessarily in any way connected to reality, is that Canon owes the world a top-flight crop-sensor body. The 70D is certainly an improvement on the 7D in many areas. The only 7DII that even comes close has lots of the features of a 1Dx: killer AF, built-in grip, dual CF, wifi, GPS, multiple settings for fps (15, 10, 5?) and perhaps a LazyBoy Recliner.
Anything that is an improvement over the 70D will have to be quite substantial in order to attract any buyers at all. Who would pay twice the price of a 70D for 10% better specs? If the specs aren't hugely different, who would buy it at all?
70D is the APSC version of the 5D3. 7DII needs to be the APSC version of the 1Dx. My guess is that Canon has/will abandon the 7D line. Building a super-spec'd APSC body would require Canon to make L-like EFS lenses, especially in the wide, fast prime range. Perhaps an EFS 14mm f/1.2? An f/2 version of the 10-22? An EFS 15-70 f/2.8 IS?
As mentioned, I am only loosely connected to reality. Oh, yeah, and make that all dual-cross 68 point AF system ECF while you are at it.