According to the Chipworks article all Canon CMOS sensors are built to 0.5 my rules, but Canons is said to build a 0.18 micron fab. With 0.18 micron they could make features smaller, thus increase fill ratio and still increase gate count. That combination my make it attractive to integrate more functionality on chip.
The advantages of the Sony design are mainly better readout noise. It helps with DR at minimum ISO. Canon's main focus seems not to be maximum DR at minimum ISO. Another way to put it. If you have problems of noisy shadows on you Canon, go look somewhere else, but if you don't have problems just be happy. Canons DR may not be the best but it may be good enough. If you shoot at higher ISOs, the Canons are not second to anyone.
Very interesting BJL and Erik, I was not remotely familiar with the technical details behind the results!
I really hope Canon adopts this clear step forward. Today I am heavily invested in Canon, if the next generation does not improve and catch up, I may need to seriously reconsider my gear investments.