18MP are enough for a canon camera.
if it would be a sony sensor then 24 MP are fine for APS-C but with canons current sensor technology that would be too much.
the problem is that canon does NOTHING to improve image quality on APS-C sensors.
instead they try to improve the hybrid AF.
but even that does not work well.
the hybrid AF in the 700D is not faster than the 650D hybrid AF.
and i bet the 70D will have the same sensor as the 700D.
again with a lower DXOmark than the 550D sensor.
that´s what canon calls progression or innovation.