rather old sensor or even new canon has one major issue..
also, there is no mood on developing new radical technologies and when they do, they keep it with minimal standards. compare 5D2 sensor with 5D3, small changes, some maybe in high isos.
Even the 6D has a better sensor than 5D3 but with fewer megapixel
And not to say that Nikon who used to have small megapixel sensors, now dominates the market more maturely in terms of resolution and noise and banding etc... etc..
My guess is that the new 70D or 7D mark2 or however they wanna call it (since they are completely screwing the names of each line production) will have a new sensor about 20-22 mp not more and of course with the same old and buggy problems such as noise in shadows and banding with an expensive price tag on.
Never understood why 60D is much more expensive than 600D
some more plastic and better ergonomics? so what? in terms of quality is ABSOLUTELY the same and costs almost the double!