After reading the report, it sounds to me like this was primarily a stupid pilot issue. While they brought up some problems with how the operation was being run over there, I'd want to compare it to how the military was operating their own aircraft. Not saying they weren't doing it better, just saying that it should be investigated. I'm not sure how the military operating the aircraft themselves would have made things much better, unless they weeded out stupid pilots.
If the pilots had taken a known route and followed the company procedures, it seems like that would have prevented the accident. That said, the references to a lack of way of communicating the flight was terminated sound like an area issue - how are you supposed to call to tell someone you're there when your phone doesn't work?
The NTSB synopsis at the end brings up a lot of good points, namely that it's virtually impossible for DoD, NTSB, or FAA to keep an eye on these operations half a world away. So it would seem to me that the military is the only group who can keep an eye on such operations.
As to the aircraft, I have a friend who flies CASAs. He's not a fan, prefers the DHC-6s.