Thanks Alan. It was more of a rhetorical question, based on exactly the points you emphasize. Often you neeed to "sacrifice" some part in order to get the part you really want, because the camera/film/sensor you have can't get it all. We've all lived with this for years and had to make those decisions on what to keep and what to sacrifice. I used to use slide film and chose to live with the lower DR because of the immediacy of slides when viewed with a loupe or projector, even though negative film had more DR.
I was just responding to a comment that implied that "if you think the extra DR might be useful, you don't know how to get the mythical "proper exposure" - obviously a ludicrous argument. As you desribe, the "proper exposure" is often one in which you make the sacrifice in the less important part of the image. The extra DR just means you make less of a sacrifice in those situations where the image you are capturing has important highlights and shadows.
Yes I supplied the answer as it seems that there are quite a few who just want to ignore this issue. Until we get sensors with thirty or forty stops of useable DR (assuming some new magical materials are developed that will provide those sensors) we are always likely to find situations where we need more DR, and so are faced with these choices. Even the magic Exmor sensor will find situations where it runs out of DR so you are back to making choices.
Would it be nice for Canon to be able to use the Exmor technology, of course, but while they are prevented from doing so by patents that is unlikely to happen. Then there are all those users who are having to regularly shoot in very low light conditions, with ISO values above ISO 1600. For those users the Canon sensor is actually still superior although you very seldom seem to hear about that fact. Of course what would be optimal would be to combine Canon's analogue amplification, with the on chip Exmor ADC. If it were possible to do this one could potentially have extended DR at both low and high ISO values, the best of both worlds.
The Canon sensor also offers the possibilities of dual ISO, as has been shown by Magic Lantern in some bodies. Combine dual ISO with say a FF 40 Mpix sensor and you have the potential to leap in front of Sony and the Exmor sensor for DR again. Imagine 20 Mpix at 100 ISO and 20 at 1600 or 3200, that would I think answer the current critics of Dual ISO and it's effect on usable resolution, although of course 80 million sensels, sampled to 20 Mpix would give the optimum results in a dual pixel scenario. A sensor like that would offer real options wouldn't it.