Hey Scott, I think with images like these it’s really about what you want. I have seen images from the dunes in both high and low contrast and while they are the same subject they have different points entirely. Based you your caption, you were caught by the excitement of the moment which is probably what led you down the high contrast road which isn’t bad at all. I think you’ve handled it really well. My suggestion would be to try to balance the shadow areas, by that what I mean is that the immediate shadow on the lower left appears much more open than the shadows in the mid ground and on the right. One thing you could look at doing is keeping that shadow as is and progressively opening the shadows as they move further away from your view point OR you could darken it to try to match the others.
Again, this is my opinion, but I tend to try to have my darkest shadows closest to me and then as things get further away the shadows are softer and softer (helps emphasize the sense of depth and it is a natural effect of looking through the atmosphere).
I echo what David said about the darkest shadows in the foreground. I learned recently that is a technique in painting to create a convincing look based on how our eyes perceive things. Very nice colors and the overall balance between light and dark is fantastic.
Real nice dune image and your processing looks spot on to me (I tend to like high contrast dune images). Having cut my photography teeth on Velvia 50 with a 4x5, the dark shadow areas look perfectly normal to my eye. This one is all about the warm light on the dunes and where that leads me, not what is hidden in the shadows. The shadows are the steering mechanism. My take, anyway. Looks good.
The shadows (and processing in general) look good to me.
This is something of an extreme nitpick, but the horizon in the upper right corner (URC), creates an optical illusion that makes it look like the image isn’t level (it looks tilted clockwise). I brought the image into Photoshop and threw a grid onto it, and the horizon actually is level until you get to the URC. Maybe try warping this a bit in that corner to make it look more level.