I am aware of at least 1 fatality involving a rider wearing a drysuit - blown out to sea in sideshore winds that shifted side-off, near sunset during the cold season (November? Connecticut?)
yes, there was a fatality involving a guy wearing a drysuit, but there is no proof that his death was because
of the drysuit. if he had been wearing a wetsuit and died, would he have died because of the wetsuit?
you got most of it right though, he got blown out to sea in sideshore winds that shifted offshore, near sunset, during the cold season. it was nearly dark when his kite went down, most of the search was done at night, nearly impossible to find anyone then.
he ditched his kite before he got too offshore, unfortunately, this was not enough. note, he was not wearing a pfd.
regardless, polypropylene and fleece keep warmth even wet, and there is no circulation inside the drysuit.