The skydome scattering shader actually works great when the density of scatterers in the atmosphere is very low - as in good visibility and high altitude. Here's Nevada seen from 80.000 ft (say, out of a Blackbird, although I just did it with the ufo) with a visibility of 250 km (would probably still be way higher in reality, but hey...) . Apart from the repetition problem of terrain textures which is *very* obvious from that altitude, it looks okay to me.
The trouble is that there's no seamless path going there - there isn't any setting which gives you this and still looks okay on the ground. Part of the trouble is that the scattering shader isn't designed to handle 30 km visibility properly, another part is that I'm not sure the altitude dependence of Rayleigh scattering is actually correct - looks always a bit on the thin side on the ground...
So, if you ask me, the bottomline is: You can't use the scattering shader for any low (<100 km) visibility, even with a bugfix to force fog to the same color as terrain, it wouldn't be credible for <20 km visibility because the whole physics of the shader code makes the approximation that visibility is large. You can use it to good effect at high altitude and high visibility, but you have to manually switch from the normal skydome to the scattering shader one and configure it, and the same setting won't work on the ground.