It is sad when somebody is killed doing something spectacular with skill.
I would have thought that anybody looking at a BD5 could understand that it's not going to be a Cherokee to fly, and that you wouldn't want to crash in the thing. Most of the pilot reports I've seen say it is actually milder than it looks.
Obviously the mid-70s BD5 saga is one of the best known in aviation. A lot of people lost their deposit money. That said, and despite having no piston engine that would work, it launched the modern homebuilt aircraft industry and changed everything that followed in that way. Burt Rutan started his career sorting out the BD5 aerodynamics and testing, subsequently going on to do the same thing better under his own control, with real engines.
The BD5 was a program that pushed every boundary. It doesn't make it a good aircraft (you don't see a whole lot of them in the pattern on most Sundays
) but it was surely significant in terms of changing everything that followed.