Atleast you admit that having that ABILITY is nice, unlike those who claim that sensor does not matter.
Now imagine having all 14.4 stops of D800 DR rather than 11 DR that 5D3 has.
I really don't know how to put this one to rest. The D800 does NOT have 14.4 stops of dynamic range. Not as a physical capability. That is a fabrication, thanks to the clever way DXO's software DOWNSAMPLES images. So, a few things here. First off...strait out of the camera, even DXO claims the D800 has 13.2 stops of DR. That is hardware dynamic range...we'll get back to that. Second, DXO also clearly claims that to acheive the "wonderous 14.4 stops of DR", they had to downscale that HUGE 36.3mp D800 image down to...a measly 8mp 8x12" print. If your buying a D800 to print at 8x12", your wasting a hell of a lot of money. Second, most people simply use some form of basic averaging to scale their images, which is not going to result in 1.2 stops of additional shadow DR...not by a long shot. You AVERAGE the pixels in the image...including shadow pixels.
For those who don't actually downscale their images, or who crop, your only going to get what the hardware is capable of. DXO measures that at 13.2 stops. I don't much care for DXO, but I still trust that within the microuniverse that is DXO, their results are consistent and "accuratE". If DXO ever came out and claimed that the unmodified RAW was capable of 14.0 stops or more, I would immediately lose the last ounce of trust I have in them, since its impossible to capture more stops of DR than the bit depth of the sensor/adc/image processor. At best you could probably extract...assuming the best real world efficiency possible, 13.9 stops of DR, possibly to another place or two of precision. So long as the final DIGITAL output is still 14 bits, you can't do any better than that. If you intend to use all the pixels the D800 has to offer and NOT downscale, then you can't get 14.4 stops of DR, regardless of how clever your downscaling algorithm may be. Your getting the hardware's 13.2 stops of native DR (what DXO calls Screen DR).
A lot of people will argue that you can use cleaver dithering algorithms when downscaling to expand the dynamic range in the shadows. They are absolutely correct, you can...and DXO's specialized software probably does. But for 99% of people who use normal-people tools, such as Photoshop, to do their scaling...they are using decades old algorithms like bilinear or bicubic scaling. Basic filters based on your simple averaging algorithm. Shadows are averaged, not dithered and deepened, when scaling...so while most people might gain a small amount of DR improvement when downscaling due to noise averaging, they aren't going to be significantly deepening the shadows...and certainly not by 2.4x (1.2 stops).
Finally, its been demonstrated by a number of reviewers around the net that Nikon tends to overexpose a bit relative to Canon cameras. I suspect thats due to the fact that they allocate more levels to the shadows (considerably more than most other camera manufacturers), which is a significant reason why they have such amazing shadow recovery...its not solely due to lower read noise (which would restore a few more levels of luminance to full usability). That leaves fewer levels for the highlights, which is often why you see blown or very nearly blown highlights in sample photos and videos comparing Nikon cameras to Canon cameras in extreme DR scenarios.
I'm not arguing that Canon can achieve 13.2 stops of DR like a Sony Exmor sensor can, but I believe they are capable of more DR than they are generally given credit for...due to how they allocate levels during read. I was able to massively over-expose the photo in my original post, such that most of it looked white, and recover. A D800 wouldn't be able to do the same...and in all probability a 4-stop over-exposure would result in unrecoverable blown highlights. Now, on the same note, you wouldn't need to bother with ETTR, or not nearly as much, to recover shadows with the D800, and their low read noise and greater shadow level allocation still gives them the edge. But overexposures DO happen...they tend to be accidental, but they also have the tendency to be more damaging than an underexposure. You can almost always recover an underexposed image to a reasonable, even usable level...since you haven't actually LOST any information. If you blow past maximum saturation in a digital sensor, those pixels are gone for good, and no amount of recovery will save your ass then. In those cases, I'll keep my Canon, thanks.