pilot fish:In short, more complex dives are being done now, with the introduction of new breathing gases, and deeper depths. Add to that the growing population of diving and you get an increase in accidents. It seems inevitable that divers will push the limits and some will have accidents.
First of all, as far as I know, there is no evidence of an increase in accident at all. Since we don't know how many divers there are or how many dives are being done, we don't have a "rate" at all. The number of fatalities reports to DAN have remained fairly constant for quit a while. In addition, aside from medical issues, it still looks like it's divers with little training and/or little recent experience who are at the greatest risk...ie, poor skills.
I don't see any evidence that technical diving accidents are more than a barely visable blip in the data. Deep dives have been done since the beginning the increased availability of more appropriate gasses and advances in decompression stratagy have only reduced the risk.
It remains to be seen whether the increase in popularity and accessability of technical diving will change things.
It's still the poorly skilled recreational diver who gets wacked most often.