You heard it here first:
18-21 Mp APS-C Sensor (Possibly back-lit)
Improved Dynamic Range
Same basic features as above plus
14 Frames Per Second
Your 7DX specs closely resemble those of 1DIV.
Of course they do. That's the direction Canon is heading.
Now that Canon has dumped the obsolete, expensive and unnecessary APS-H sensor, Canon has freed up resources to concentrate on the two most popular formats. It's perfectly reasonable to expect that the next generation of APS-C sensors will equal or better the performance of the previous generation of APS-H. Maybe even a little conservative.
Canon has said they are keeping their options open about addressing the needs of sports and wildlife photographers who want longer reach and an improved APS-C sensor in a pro-level body makes perfect sense. I am being conservative by suggesting that the autofocus will be closer to the ID IV instead of the 1D X. I could be wrong about that, but I do expect we will see improved autofocus in the next generation.
If you doubt this, well...I would just point to a thread from last June, when I suggested that Canon would withdraw from the megapixel war and concentrate on image quality in future models. People thought I was crazy, but it turns out I was right (I admit, even I'm a little shocked that I called it as closely as I did).
Really though, this isn't that hard to predict. Too many people get caught up in what they want companies to do, instead of looking at what they are doing. An objective examination of Canon's recent actions points pretty clearly in this direction.