Hi,
you shouldn't look at this from an artistic standpoint. Its just a sky covered by clouds, just like it happens most often with altocumulus, many of which come in large patches. If you are planning to use this type of cloud, but want to make a smaller and well placed patch somewhere, that's easy to do, too. Apart from all that, I think the sky looks pretty close to the real thing, which is why I was happy to be allowed to replace it with my previous altocumulus setup. Which wasn't bad, but not as good as this one.
The shadows from the clouds might appear a little dark here, but actually the GI light contribution from the sky was pretty good, it's just that the image you're seeing has been postworked to a higher contrast (which then darkened the ground more).
I've tried a sunset scene with these clouds last night. That too can give interesting result. Maybe I will post that experiement here later as well.
Cheers,
Frank
