I have been thinking about this lately and am going to make a controversial prediction:
I believe the 7DII will have the highest resolution of any Canon DSLR and I think it is entirely possible that future APS-C bodies may actually end up with more resolution than high-end full frame DSLRs.
Reasoning: The strength of the APS-C format (in addition to cost) is the perceived extra "reach" of the 1.6 crop factor. Crop sensors will never match the high ISO performance or dynamic range of a full frame sensor. But, what Canon demonstrated with the 70D is that they could increase the resolution of the sensor without sacrificing ISO performance or dynamic range.
The higher resolution 70D sensor performs at least as well as the 7D sensor in these areas. And, some argue it actually performs slightly better.
I am fully aware of the argument that a full frame sensor can be cropped to the same framing as an APS-C sensor without losing much perceived resolution.
But, that argument breaks down in cases where the photographer is distance limited and must crop the crop, so to speak. I'll leave the math to those who are more adept than I am, but just point out that a 24mp APS-C sensor can have half of its pixels cropped out and still produce a 12mp image.
Focusing on higher resolution at the top end of the APS-C line allows manufacturers to better differentiate the two formats for enthusiasts and professionals. Both formats function just fine for general purposes, but if you want to shoot under the most challenging lighting situations, full frame is the better bet. If you are a portrait or studio photographer shooting under controlled conditions, the larger format is better.
But, if you are a nature photographer or a sports photographer and you need to reach as deeply into the scene as possible without getting eaten by a bear, drowned chasing waterfowl or crushed by a 250 lb player, and need to do it at 8-12 fps, then you need a high-resolution, high performance crop frame camera that has sufficient headroom for you to crop even further when necessary.
I've long said Canon and Nikon don't want to convert everyone to full frame, they want instead to sell everyone two bodies. One way to do that is to play to the strengths of each format and differentiate them at the high end.
We all know that the worldwide camera market is struggling. Nikon and Canon need to find ways to increase their sales. It's far easier to get an existing customer to buy more than it is to find a new customer. Differentiating the two DSLR formats offers the hope of greatly expanding sales using the existing base of customers.