The 12-24 and its ilk are engineering and design marvels. Had it not been for Nikon and some of the other lens manufacturers coming up with that solution I would have had to buy a Kodak, which was not exactly a great success, gone over to the other side, or invested heavily into LF and MF Digital which, as I'm sure you know, has been an extremely expensive path to keep up with
I have enjoyed good success using the 12-24 for applications best left to other systems. A lot of that has been achieved through software manipulation and cropping to bring the scene in to a more reasonable perspective, and then maybe some more cropping to balance the composition. The net loss of pixels from this makes me cringe.
Your picture of the arch is a fine example of what can be accomplished but lets face it, It isn't exactly straight out of the camera. (It is really really nice BTW).
FWIW - I never intend to sell my 12-24. I will carry it when size and weight is a factor and either shoot with it in the DX mode or treat it like a 19-24mm zoom in FX (if the IQ works out that way). Once the 10-12mp DX mode with FX sensors becomes a reality it will become an extremely important and versatile tool once again for small kit work.
What really has me intrigued is being able to carry a 20-24mm prime, a tiny 50mm 1.8 and an 85mm 1.8 and a 200 F2 with the small body of the 700, and do most everything I now do with some seriously heavy and slower zooms hanging from a D2-3 series body, and not have heart palpitations in Europe's airports because of their minuscule carry on weight restriction. Hopefully this newfangled dust removal system will make changing lenses often less of a pittfall.
Hopefully there will be a few floating around in a few weeks and we will actually be able to talk about using the camera rather than just posture and speculate, as I am doing