"I can't say I know about the huge distance scenes, but the lighting in "Up" was magnificent and made what looks simple 100 times better than it would be in any other rendering system in 3D animation."
What are you basing that comment on? Even assuming (fairly, I'm sure

) that "100 times better" is mere hyperbole, I think it's rather presumptuous to conclude that the look of Up had much to do with this new rendering method. As the article states, what it does is make things faster, not look better.
As for the rest of the discussion, I think we're all drawing some very broad, sweeping conclusions based not only a short and non-technical article, but also on a very basic understanding of how TG2 itself works right now. I know when you say "you could use raytracing for the sky and point clouds for everything else" and "even a 2-3x reduction" it's really just a hope, but I think it's unrealistic to expect that kind of speedup, nor that implementation would necessarily be that simple.
In any case I'll try to have Matt weigh in on this. It's certainly interesting, I've just come to be very skeptical of any "magic bullet" optimization techniques, even if they come from production use with a major studio, because the things TG does are rather unique and seldom really tackled even by studios (most of the time they just use photo or hand painted matte backgrounds for this kind of stuff).
By the way, where was Vue used in Clash of the Titans? TG2 showed up in Imaginarium of Dr. Parnassus and Alice in Wonderland recently, so I don't feel too bad.

I would have been a bit more chagrined if the Vue fanboys had been right about Vue being used in Avatar (though I always knew it was just wishful thinking).
- Oshyan