I have this problem and in the first month Canon launched the 7Dii, I went through 3 different bodies, each posing their own problems.
As mentioned above, keeper rate isn't great, as it's normally only 1 or 2 shots of about 10 that are sharp. The problem to me was the pitch Canon used when promoting the camera, effectively calling it a 1DX mini. It is not
That dedicated processor that tracks colours and shapes in the 1DX is a large part of why one gets nearly 100% sharp images, neither the 5Diii nor 7Dii have it.