When all the information has been collected and considered, it still comes down to holes in the cheese, with the choice to make the flight in that weather a factor.
IFR with all the bells and whistles and the jet flying itself down to decision height is the only safe flying available in lifting fog with iceing a possibility.
Some have suggested a possible mechanical problem. The A109 was first certified in 1996, and nearly a thousand have been manufactured by the Italian company; military variants, worldwide civilian use by police and ambulance services. 250 are listed for sale at the present time, you can buy your own A109E manufactured in 2006 for only $3,400,000. If it was, like the Dreamliner, the first flying example of its type, glitches would be expected, but a twin engine state of the art highly developed helicopter is unlikely to suddenly fail.
Although this has attracted unrivaled media attention, the surprising thing is how few were the casualties. A previous post mentions that on Jan. 24, l990, a single engine Bell Jetranger with 4 on board came down on a suburban area of Glasgow during a snow shower. One on board was killed, the pilot was badly injured, and the two passengers walked away, no one on the ground was hurt.
Most air accidents hurt only those on the aircraft. Relatively few on the ground. So how much should be spent on prevention?
I can't imagine that a couple of strobes on a crane would be a major item in a developer's spreadsheet.