Experts may be able to tell subtle differences but the vast majority of people are not looking for and probably won't notice differences in DR in photos (talking about differences in DR between photos taken by a 5DIII/6D and a Nikon D600/800). Those people will be impressed by composition, colors, the content (they like their engagement photos, events, babies etc.) way before noticing (if at all) if and/or how the shadows have been lifted and at what cost
I'm not taking anyone's side here, just stating my experience with clients, friends, family etc. It's happened quite a few times that I am excited about a new feature or a new camera and trying to explain/demonstrate the improvements to my friends, family, and some cases to clients. The overwhelming reaction is something like this: "I believe you Gabe, but I don't see the difference".
This is similar to my music career and guitars. I've had about 70 (!) guitars in my life. Finally, a few years ago I settled on a Suhr S-1 Pro. However, trying to describe the nuances and very fine differences in tone, playability etc. between various guitars is really tough unless I talk to a pro guitarist. To 98% of people my USA Strat and the Suhr sounds just the same And it's also true that my particular style and sound come through almost all guitars that I get my hands on (that's also a feedback I heard from people who heard me play live or on CDs).
So while I absolutely agree that a large DR is a good thing, no doubt, I'm just saying that not all people are geeks like us and to most this remains invisible (and very low on their priority list of what makes a photograph a great one.)
Just my 2 cents...