As an owner of the 1D-X, I'm sorta disappointed with it. Don't get me wrong, I love what it is but disappointed that it should have been more. Many times I wished I had stepped down from the 1-series bodies but I thought that was a bad idea as well. I really love the 1-series bodies.
While bigger photosites are "always" better, that concept must be balanced with resolution. After all, nobody wants one photosite (imagine how noise free it would be! LOL). Of course, then the questions comes "What resolution is enough?" This is where everybody has their own opinion. Maybe it would be better if Canon also made a low light specific camera (a reasonable but respectable resolution) separate from a high resolution focus camera.
I've always felt that Canon's flagship camera should also have the highest resolution and best technology. Don't hate me, but I also want video and was very disappointed that Canon made a 1D-C. Just because a camera has video in no way detracts from its photo capture ability.
Sidenote: Honestly, if the Canon 1D-C was only 4k (at 4096, not TV's 3840) in resolution in both photo and video might make a pretty bad ass camera setup. I would definitely pay $7k for that, not sure if I would pay $15k but it would be tempting (especially if it has 60p and a global shutter). This would also make an awesome low light camera too.
Since most of my work is in a controlled lighting situation, I want a higher resolution. Something around 30 megapixels would have been enough when the 1D-X was released but today I think Canon needs to make a statement against Nikon and produce something around 40.