If you put your clients inside of their virtual houses inside of VR I think they could care less about perfect shadows and reflections. Resolution will suck for a while anyway. Archviz people seem so hellbent on quality they forget the simple pleasure being able to move around in your own space as opposed to just looking at pretty pictures.
With real time GI around the corner, I ask what’s better? Perfectly baked but static GI or or the ability to change the time of day and turn lights on and off in the house? Download and play around with this if you haven’t already. It’s Cryengine, but completely dynamic GI with just 2 bounces.
http://www.cryengine.com/community/viewtopic.php?f=309&t=131523
Oh and I’m shocked at the ignorance in the reply of rebusfarm. Whatever makes them think that UE4 will go away for archviz? Maybe I just don’t understand the space enough to grasp how any client would prefer pretty V-Ray pictures over the possibility to actually walk around in a house?