What risk? In many races around the world (AC series) with many boats with many accidents and many sailors involved nobody got seriously injured. Regarding the development of the bigger boats only two accidents and an unfortunate dead...
I am surprised that you are willing to make a statement like that without a shred of statistical support.
The first thing you do in assessing risk and safety is to normalize the number of accidents and injuries on exposure hours. OSHA specifies a total recordable case rate, which is the number of injuries per 200,000 man hours. It is a very good metric, because 2000 hours is a typical number of hours worked by a full time employee in a year. So the TRC rate gives, on average, how many injuries would be suffered in a year by a workforce of 100. It's a very nice way to put it. In addition to TRC for injuries, you can do the same calculation for near misses, first aid cases, and fatalities, and stack them to develop a safety pyramid with near misses on the bottom and fatalities on the top. Typical benchmark pyramids exist that can predict how many fatalaties you might have in the future based on your history of less severe injuries. Unfortunately, AC72 has already started to fill in the top of the pyramid.
It would be pretty straightforward to calculate a TRC and fatality rate for a common class of monohull racing, and then do the same for the AC72s so far, and compare the rates. Then you get a much better picture of how safe/unsafe the AC72s are relative to other boats.
It would be a lot better than simply saying "only two accidents and an unfortunate dead." I suspect that a calculated TRC would show these boats to be much more dangerous than any predecessors.