The XD (7D) body was meant to be a test bed for the features found in the 5DIII, 1DX and other future cameras and was DESIGNED AND MARKETED to be the flagship APS-C camera.
Now, tell me WHY Canon would "upgrade" a dying, "downgraded" XXD class body in favor of dropping it's current flagship XD line? (7D)
The 7D upgrade (7DII) WILL remain APS-C AND the flagship camera body, you can bank on it.
The 7D is the top prosumer sports body and that is a niche that Canon have dominated for some years.
There is no reason why Canon cannot trickle down and improve this technology into the 70D - the traditional nomenclature for the prosumer range
In place of the 7D a new sports body would be needed to surpass the 70D. I dont believe the technology is important for the sports camera however it would have to:
- be good for birds/wildlife
- be good for sports
- be good in low light
- be good at higher iso (to keep the shutter speed fast)
- have good IQ/DR for bigger prints
There are 3 current technologies, APS-C, APS-H, FF
The difficulty here is that APS-C and FF fail on several points whereas APS-H is good (not excelling) at all of them
I believe that the EF-S issue can be discounted for a sports camera as the sports lens are all EF. Those with the high value EF-S lens would have a 70D which be at least as good as the 7D - perhaps with the same sensor as the 650D plus other enhancements
That leave APS-H as the easiest technology to use - as it has already been developed into the best sports camera, So trickling that technology down to the sports camera would cost least, be quick to get to market and give Canon a high profit body (due to the low R&D)