55 KIAS was the proximated forward speed of the a/c, it was said to have "entered the dive at about 50 ft agl", there is no speed mentioned at impact.
Though a ground contact speed was not mentioned, it would not be less than the stall speed for the plane, as the plane contacted the ground near vertical. If the plane contacted the ground in a descent, something like a landing, then yes, the vertical speed could be a few knots, where the forward speed were still flying speed. In any case, the visible damage to the plane, zero ground marks showing deceleration at ground contact, and the fact that the pilot died, are evidence of a high deceleration force. I know for a fact that a 14+G forward crash is survivable with injury.
Is there anything new to learn from the tragedy?
Nope.
So sad, so unnecessary, but is there anything more we can do to stop this sort of thing happening again?
Hopefully, discussing it, and impressing upon new pilots that there are things planes cannot do, or might only do, if flown with above average skill. Figure 6 shows a needlessly nose high pitch attitude, which would prevent acceleration to a safe flying speed. The pilot got it off the ground, which sounds like an achievement in the conditions. Lower the nose, and let it accelerate!
He was also “not the most consistent student”. He
described him as one of the “more aggressive, pushy students” at times. He added that
during some of the first few lessons they flew together these attributes gave him cause to
“reel him in” at times and he had to explain to him what was acceptable and what was not.
He added that he had to be quite firm with him at times.
Is concerning. This should be recognized by the instructor, and, yes, reeled in! Some new pilots have unrealistic opinions of their own skills relative to airplane performance, and need to be "told" for their own good. If they will not listen, that's a big red flag. I've encountered a few such pilots, and had to take extra steps for their own safety.