LW50 and NF ask excellent questions.
On the question of weight: Would these 17 fatalities been avoided if the crew has SS6 floats appropriate for the Atlantic and been more comfortable ditching? SS4 is only good for ditching along side those in d'Nile after all.
I wonder how the trade off was made on the failure to achieve 30 minutes running after a loss of lubrication. There was over 2 years from the failed test to entry into service and over 6 until Cougar. So time to act. Too expensive (like the Ford Pinto) or too heavy? Another Sikorsky helicopter had a total oil loss in Canada in 2002 so the alarm bells should have been ringing with Sikorsky and the 'extremely remote' argument was already 'optimistic'. Or should we just going to hear the FAA were to blame for letting Sikorsky deliver the aircraft?