> It is possible (and IMO very likely) that this aircraft is fundamentally unsound, by design
"Fundamentally unsound" seems like a subjective judgement in an area that clearly requires numbers.
Wikipedia tells me there are 1445 of these planes in the air each flying, what, 3000 miles a day on average? The existing accident statistics would argue strongly that this plane is "safe" in an absolute context, even if it's clearly "more dangerous" than other models. The big reason people are so upset about this is that it's a safety outlier in an industry that has been extremely safe, and getting inexorably more so, over the last half century.