As far as CPU vs GPU:

I don't think CPU vs GPU has to be an either/or proposition anymore.  Arion is an unbiased renderer that uses a combination of CPU + GPU working together, and I think going forward that it's likely CPU + GPU (rather than CPU vs GPU) will be the new paradigm that more and more render engines move towards.  I know that TheaRender (another unbiased renderer) will be releasing a CPU + GPU around Christmas time, and I have no doubt that Octane probably has something in the works for this as well, as focused as Octane is on speed anyway that just makes sense.

I was blown away back when Octane first came out and some of the renders (and the blazing fast render times) started getting posted on the DAZ Carrara forum.  The only reason I never got Octane was because I've never (yet) had a computer that could run it  :)    Near the same time, Reality was just starting to make it's first impact and I started seeing Lux (via Reality) renders appear in the daz forums as well, via those users of Reality that were using Studio.  Again, the quality of the unbiased renders was just freaking excellent, but the render times people were talking about was just unreal... 20 hours to a week in some cases.

So I knew I wanted to get an unbiased renderer, but found Lux way too slow and didn't have the hardware to use Octane.  Eventually I tried Thea out and found it was a pretty fast CPU unbiased renderer, so I went with that, though it did mean exporting my Carrara scenes in .obj and retexturing once I opened them in Thea again.

By the way, I don't think Luxus is at a stop; just a couple of weeks ago Spheric Labs put out a new release for it, fixing a few bugs.  I picked up Luxus a couple months back and have had some good results with it, though I have yet to master the texturing the way I would like.  Lux itself is still just so slow to render, though I'm sure I might have a different opinion if I had a computer that could run the GPU version of Lux  :)

But I'm already trying to plan out what my next rendering computer will be, to ensure that it can handle GPU rendering, and I really do think that CPU + GPU is the best model to plan for.

I think it's excellent news that Octane is planning to develop a plugin for Carrara, and I really do think it's a good thing for Carrara.  This in no way pulls resources or time from the actual DAZ team developing Carrara, so I certainly don't see any downside, and a lot of upside.  

I think this thread may have wandered a bit into the realm of theorizing what the Daz Carrara development team should be spending time/effort on, and since the Octane plugin has nothing to do with that at all it really is a bonus to Carrara users (those who can use it), but doesn't subtract anything from what the DAZ team may (or may not) be developing.

I do think that if Embree really can speed the native Carrara renderer by up to 30X, that that would be a huge selling point, and the DAZ team would be well-served to put some development muscle into phasing it in.  Among biased render engines, my personal opinion is that Carrara is pretty damn good (admittedly I use full GI nearly all the time as it doesn't seem to add prohibitive render times, at least for the type of renders I tend to do), and anything at all that could substantially speed the render times for the native engine, even 2x much less 30x faster, would be a big selling point I would think.