even if legacy ignored clearance to descend and radar and radio contact were adequate with 737, a heading change or altitude change for 737 could have solved the problem.
there will be room enough for blame...a bit for ATC, a bit for legacy, a bit for unknowns.
the rate things are going, I expect to hear something within 1 week, definitive tapes from ATC, CVR's from both planes, and perhaps most importantly, the FDR from legacy...if making many maneuvers, 5000' altitude changes as has been suggested, coupled with loss of transponder on ATC radar tapes...we may have a cause.
mentioning early posts about offsets, maybe it is time to go to "one way " airways...with gps, we no longer need to go over the top of a VOR.