Haha I walked into that one, I don't shoot much landscapes so was wondering if realistically 10-15 stops of DR was enough.
Always depends on the subject. Most studio shots like the image below don't need a huge dynamic range from the camera, as the light is totally controlled. A couple of images from stevelmx5 above are situations where more DR could be beneficial. The first image may have got more detail in the candelabra and the lights on the wall. Would it have made a huge difference to that image, maybe not, but why not want more DR!
Outdoor images on bright days with dull or shaded foreground can push cameras to their limits of DR. Sunsets too could be enhanced by more DR. Some people use graduated filters to try and balance the exposures of some scenes, but sometimes that is not easily done. Some people take multiple bracketed images and merge. Some take multiple bracketed images and HDR. Why would anyone like to have to do that less often!
I don't understand why some people, unless they are purely a studio shooter would not need more DR sometimes. Unless one is only a studio photographer there must be situations where something in the scene is over exposed and there is little detail in the darker areas at the same time, why would someone not want that to happen less often!
This is not aimed at you, but sometimes when people on forums say an improved feature is not important, be that resolution, DR, Fps High ISO performance or whatever it may be because their current camera is not as good.
Obviously there are those which some features have no relevance to the images they take, but sometimes though, it may be because a new camera is deficient in an area or two, and they want to like the shiny new thing.
It is like the Canon users saying that virtually no improvement in the 6D replacement in DR after 5 years of development is not a bad thing.
Why would anyone not want more DR even if you think you may never reach those limits!
Shouldn't a FF camera sensor not be better than a similar megapixel crop sensors in every way? If I was buying FF I certainly would.
I waited 6 years for Nikon to improve the D300S in almost every way. The D7***s were not anywhere near being good enough replacements for me as they would have been only sensor improvements and losing other features.
Thankfully the sensor improvements where huge added to all the other improved features. 
I was very close to switching systems and getting a 7DII for the overall improvement I wanted though after waiting so long. Thankfully Nikon came to their senses.
Testing A7 and Samyang 14mm 2.8 by Steve Lloyd, on Flickr
Testing A7 and Samyang 14mm 2.8 by Steve Lloyd, on Flickr
Testing A7 and Samyang 14mm 2.8 by Steve Lloyd, on Flickr
Testing A7 and Samyang 14mm 2.8 by Steve Lloyd, on Flickr
Testing A7 and Samyang 14mm 2.8 by Steve Lloyd, on Flickr
