As the new 5DIII starts to appear in the real world I think I'm starting to get a better feel for Canon's strategy and, I must say, it seems pretty brilliant.
When Canon announced the 5DIII they placed a lot of emphasis in their announcement on the camera being the result of feedback from professional photographers. But, of course, "professional" is a very broad term that can cover a lot of very disparate specialties.
Now that we are seeing some examples of what the camera can do, it seems like they focused on one particular, but very large segment of the professional market – wedding and special event photographers.
Early examples seem to show a camera that performs very, very well at higher ISOs. Not necessarily in the stratosphere, but rather significant improvements in the 1600 to 6400 range. A range that I suspect many wedding photographers find themselves needing. The autofocus improvements, of course, benefit everyone, but event and wedding photographers don't get the chance to refocus their shots, so improved autofocus would certainly be beneficial.
At the same time, the camera is very well-equipped for ordinary studio work under controlled lighting situations. So, no compromises for studio work but more flexibility in the field. Not to mention some improvements in video for those who need to use it for that purpose as well.
Now, of course, the camera is great for other purposes as well, but it does seem to have some significant improvements that will benefit a large and very competitive segment of the professional photography market.
In short, what I am saying is that it seems as though Canon really did study their market closely and may have produced a camera that is intended to sell, rather than a camera that is intended to be popular on forum and testing sites.