Agreed, dangermouse - the best ideas are developments of existing technology.
This design will have benefitted from recent software developments in Computational Fluid Dynamics and Fluid Structural Interaction. From the image (assuming blade droop is not playing with perspective) it looks like this design takes the BERP concept to the whole outer 1/2 span of the blade. The biggest problem would have been controlling flexure and stress from centrifugal and inflight loads. Turbine blade designers have hours of fun trying to make sure the section shear centre, inertia centre, and aerodynamic centre stay consistent along the span. With this much sweep i'd be interested to hear what sort of fun the blade structural & design guys had. Notice how the sweep back extends just a little beyond the sweep forwards for example.