I for one was very excited to see this project, and I still am. There's no point making absolute pronouncements of superiority, IMHO, but in comparison to the "standard" projects seen here and elsewhere, this is a step in a new and fun direction. At least, I haven't seen it before, but I certainly don't see everything. Poke holes in the design? Sure, but we can do that to anybody, if we wanted.
Furling: Alternatives to the folding tail abound. Powered yaw, for example. That's not "simple" or passive, but it's a good protection mechanism for those who like that kind of project. I like what Frans has come up with because it does something well, even if it's not super-simple. Who really cares if it's simple, when it's being done purely for the joy of exploring an interesting idea.
So I'm keen to see more!
I had an idea Frans... Have you considered a clutch in the actuator shaft? When there is a control system failure, power is lost, or an error condition is detected, the clutch opens on the pitch shaft. If you had a spring on each blade, they would turn to a feathered position, immediately stopping the turbine. Normal operation would require a small amount of power to operate the clutch. Note I'm not implying that the driven power shaft should have a clutch, just a small one on the rod that pushes out the pitch control "spider".
Making the bearing pillowblocks from aluminum will improve their resilience to weather if you intend to operate the turbine over the winter. With the right combination of shoulders and bearing sizes, you can combine a deep-groove ball bearing and a tapered roller bearing, or double them up like a trailer axle. By the looks of it you would have already thought of these things, just haven't had a chance to try them yet!