Thea for Revit would be a good move, especially for the US market. I am an architecture professor and I can confirm that Revit skills are expected by employers there and almost every architecture school teaches Revit as a major design tool now.
I want to throw in a vote for Houdini here.
I already spent my poll-vote on Lightwave, but recently got interested by a job for a film studio (that I did with Rhino/Grasshopper) in Houdini. I am aware that Thea ATM isn't the typical and best renderer for film FX where Houdini excels, but I saw some Octane integration videos for it and thought it might not be that bad if some good links to the node system can be established, so that parameters can be influenced not only in the current rather static way but also in a more generative, node-thinking way.
Would be interesting actually to break up Thea materials and layers etc. into nodes...
Would be great to integrate it with Grasshopper for Rhino too - the Rhino developers currently integrate Cycles as render engine into Rhino 6 WIP and already showed a preview for Grasshopper nodes being used for shading.