Cutting edge or not, two things stand out to me here. One, many light sport aircraft have speed and G limits that the pilot has to be mindful of. And pilots of light sport aircraft often are on the lesser end of experience, since one can get a ‘sport’ license with less time and training than a full ‘private’ license. Second, any flight over water can become disorienting very quickly depending on lighting, altitude, visibility, and again, pilot experience. I have no idea if any of these were factors in the accident.
There are go2pro videos of him skimming the water and being thrilled to death. How about strong gusts hit the airplane from behind and force the nose to dig into the water, flipping it and killing him?