Most comments on this thread have been generalisations, and there's nothing wrong with that. But with regard to what, if anything, should change in the US EMS industry to reduce the clearly unacceptable accident rate, it would be interesting to look at the specific error that caused each of the accidents over say the last three years.
Was the fundamental error breaching existing operating regulations and procedures? Was it bad pilot judgement operating within the regulations? Mechanical failure? Etc.
If anyone's got the time and interest to go through the records and come up with the detail of the accident causing error I think it would make interesting reading and point to the changes that would have the greatest effect.
For example, the fact presumably is that hundreds of EMS missions take place in bad weather at night each year, many to unprepared sites, and not only do they not crash, presumably the pilots do not think they are taking unreasonable risks either?
So what makes the difference? Surely, luck rarely comes into it, unless its your turn for the statistical chance of mechanical failure?