I would expect more megapixels is going to challenge the skill of the user.Joseph Holmes would
certainly agree with you.
They're long articles on medium format shooting technique & precision, but well worth a read.
The summary is that merely using a "bomb-proof" tripod, using a cable release, waiting 6 seconds for mirror vibration to settle after lock-up, and using a 3x magnifier on the focusing screen is not good enough to get the full 40+ MP resolution out of a medium format camera system.
Phase One's tolerance for registration distance is 12 microns, but he's come across systems that were off by hundreds. Joseph calculates that with this system's lenses the difference between the focal plane registering at infinity and 200 feet can be as low as 8 microns (depending on the focal length). Among other things, he had to test *seven* 80mm lenses to find *two* that would really, truly focus to infinity at the micron level (meaning everything at 1000+ feet sharp; remember that we're talking about the mechanical tolerances of lenses in distances of microns here). Other lenses worked out better, but you get the idea. I'm not talking about the resolution of the glass or sensor here, but simply the mechanical tolerance of medium format lenses & bodies.
If Joseph had to go through all this to really squeeze all the resolution capability out of a high-end hand-assembled ultra-quality-controlled medium format camera system costing tens of thousands of $US, how much resolution do you think non-professionals will really be able to effectively eek out of a mass-produced 30+ MP DSLR with even smaller pixels, mass-produced lenses? How stable is "stable enough" from an I.S. system? How much will the strong AA filter Canon tends to use impact the real capability of such a sensor? How precise is phase-detect AF at these resolutions (even after calibration)? And let's not forget that ultra-high resolution CMOS sensors like this tend to stink for video...
Mind you, sometimes Canon's approach to this sort of thing is "ship first, ask questions later" so who knows, but personally I think that they're purposely avoiding the high-resolution game as it would open up several proverbial cans of worms for them, none of which are economically lucrative for them to deal with.
Have a look at some of Joseph's samples BTW, they're truly stunning in terms of resolution.