If Canon bring back the APS-H, It must be in the niche market and meet the following requirement.
1. Smaller than the 6D for portability
2. Same pixel density(or even smaller) than the 1Dx for low light/high ISO performance.
3. Very fast FPS for sports photographer due to lower MP.
4. At least half of the price of 1Dx
Question is at this day of age, how many photographer can live with a 10 to 12 mp camera as a general purpose camera?
Why does it have to be smaller than the 6D when you're going to be hanging big whites off it?
I think a 7D size 24+MP APS-H body would be attractive since the 1D4 is 16MP and $3500 complements the current line alongside the 5D3