Mario,
My compliments on your research into this accident.
I agree with your conclusions, there are obvious violations of basic safety protocall (3 diver team, 1 missing, surfacing diver contiues to dive alone etc)
3 man teams are risky in the best of times.
Had the surfacing diver reamined on the surface until the other 2 team mates surface, this could have ended differently.
As a user of the OTS buddy phone system, I agree that communications may have aided and perhaps prevented this tragedy, but, the comms are line of sight only, and a diver on one side of a wreck cannot communicate with a diver on the opposite side, which may have been the case here.
Full face masks are indeed safer, but the fact remains they and the buddy phones are cost prohibitive. At $800 - $1200 a pop, I don't think we'll see many jumping on that band wangon very soon.
My contention here is that strict adherance to the proper buddy system would have solved the problem, as apposed to a technological solution.
Mike