Even if only the blade area is considered, the Cp of 0.22 looks very high for this sort of drag-based blades.
That said this design (photos pages 25, 26, 27) seems better because the blades are better shaped, in addition to the ““clamshell” blade design”.
I think they could have tried the rope drive transmission instead of having a heavy and slow generator in flight.
Certainly these projects do not seem to have been followed up, but the same is true for the other projects in progress.
We should not wait for AWE to compete with HAWT, but try to see how each method can be improved, the difficulties encountered differing depending on the method.