Well, I wouldn't mind some sort of enhanced hiding, whether that's just a boosted Hide bonus or even more. It's the extra senses I have a harder time justifying.
How about they gain total cover and a +20 cover bonus to Hide checks?
That's enough for me!
I think background is the only thing remaining. Something like "Dune dragons are normally solitary creatures with only a broad society. Nonetheless, when not keeping to themselves, they are often willing to converse or even at times ally with adventurers --- as long as their treasure is undisturbed."
Also, I just spotted a "sand dragon" in the breath weapon.
"Dune dragons are normally solitary creatures with only a broad society. Nonetheless, when not keeping to themselves, they are often willing to converse with adventurers, even going so far as to provide helpful information --- as long as their treasure is undisturbed. They sometimes bury their hoards deep under sand, usually near but not always in their own lairs. While dune dragons might live either in deserts or on sandy beaches, they have a large range and wander far from their usual homes."
Sure, I like it!