Aviatornovato : Your vision on how ATC should be regulated and performed is just that : a vision, a concept, based on 100% safety at all times trying to take into account all possible failures and multiple failures combinations. It is laudable, if applied traffic would be reduced to such an extend that it will not be economically viable.
Safety in Aviation is always a trade off . In ATC, safety is first, but expediting the traffic and providing capacity to cater for the continuous traffic growth is a very close second.
As an EASA ( European Aviation Safety Agency )top official recently said : Safety must not restrain the market "
You have to understand that a pre-departure clearance , past the first altitude, point to be flown to and SSR code becomes more a " wish list" than a contract set in stone.
Arguing a criminal case against pilots or controllers based on incomplete or incorrect pre-departure ATC clearance will be easy to wipe off technically.
On the transponder issue : More an more ANSPs are declaring their airspace SSR only ( Portugal for one ) making a loss of Transponder a real safety issue. I would think that to pass a proper safety cases States relying on SSSR only for their ATC , a proper warning in the cockpit that SSR has failed would be an mandatory item.
I am surprised that after this accident the NTSB only " believes that the FAA should require" i a warning . For me, and there I agree with you, the lesson to this accident should be asking for a modification .
And I am not adding the TCAS issue.