I have serious doubts that a feathered reentry would work for anything that has orbital reentry speed. There's a reason we have capsules with heat shields, and it's still tricky. We lost a shuttle over damaged heat shields. I suspect there would be strong vibration issues at orbital reentry speed as well that they haven't had to face yet since all of their flights so far (as well as those actually scheduled) have been sub-orbital. That being said, I wish them luck and hope they continue to innovate.