OK, I'll bite.
The issue with the Tomahawk's structure stemmed from the fact that the number of wing ribs in the non-conforming prototypes was reduced for the production models, but the spin testing was done on the earlier wings. The result is that sometimes, under some loading conditions, on some airplanes, when the airplane spins the wings apparently will oilcan enough to throw off the recovery dynamics and cause the spin to flatten. The problem is that these reported incidents generally cannot be replicated reliably, and they happen unpredictably.
Yes, there is video around of the tail shaking like hell in a spin, but to my knowledge no accidents have been blamed on that.
I will mention two data points on the question of the wing structure. The first is that Bill Kelly, Piper's chief engineering test pilot a few years after production began, had a scare in one when it would not recover from a normal upright intentional spin. As a result, he refused to fly another one and recommended to Piper brass that they buy back all the T-hawks and destroy them. Obviously they did not take that advice.
The second instance involved a DPE who was an accomplished aerobatic pilot and, as I recall, a student on a checkride. They got into a spin and the aircraft would not recover until both of them unbuckled their seatbelts and leaned forward on the instrument panel to get the nose to drop. I'm going off memory on this, but as I recall the aircraft recovered with a hard pull a couple of hundred feet agl and was structurally damaged in the pullout.
As a result of these kinds of incidents, there was concern that certification standards had not properly been followed because of the use of both conforming and non-conforming prototypes. The FAA did a paperwork review and concluded there was no reason to dig further.