Blender's license and API type does not make the integration impossible (as proved by Vray), but rather difficult, because we need to go through several layers to circumvent the licensing and to convert to C++. Which is why we are not doing it at the moment. That might change if blender becomes more powerful and popular. We are watching it. But no work is being done, no plans to do it right now, and no "threshold" when we would start is set. It might happen, it might not.