Of course, I know you are working on this, still I’d like to give some more feedback… (Which is just, because I am curious and would like Cycles to be cool in 6 weeks instead of 12. Or so.)
Large HDRs seem to no longer crash Rhino immediately, but light and shadows, when using them, still just look like not right. (Though I couldn’t describe that “right”…)
When e.g. a pretty low sun comes from west:
I get this:
The result looks quite nice, but the shadow is too short and too soft.
When I use “Show shadow only” for the ground plane (to get rid of the horizon), it looks like the white reflection from the second image turns into a shadow or too dark reflection and on the right side I am not getting any shadow at all:
And when I then “Reset To Defaults” the shadows/reflections are the same for intensity 0.5 and 1.0. I just used a color picker tool to check that, but they both seem to have the same range. (In the second image here I just changed the default Studio’s intensity to 0.5…):