Including an accurate lighting model? Or do you think that there's a significant inflection point before that when we're still attempting to replicate a final render using rasterizers?
(My current bee-in-bonnet, besides integrating HMDs and mocap, is realtime-ish path tracing - but that's a while away yet, still.)
So what would you say - as one of the people involved, rather than a journalist commenting - are the most interesting/important parts of the project?