Your referring to pixel count on the sensor? I imagine it was their intention to stay with a conservative resolution for two reasons. 1. Performance 2. Minimize cropping on 4k video. The camera is focused on speed and performance regarding auto focus, image processing, FPS, and ISO both for professionals still still and video. I think Canon made a calculated move here to hold back the MP count to ensure the highest level of performance out of the sensor possible, its pretty easy to see that the bytes of data increase extensively as pixel counts go up. 20Mp may have been a bit conservative but it is enough for most applications, that is unless you want a several foot wide gallery print made. And honestly if that's the goal you'd probably be better suited shooting medium or large format instead.
