At “my“ airline it is always mandatory to execute an escape maneuver if you receive an unexpected GPWS warning, irrespectively of flight conditions. Unfortunately will current GPWS systems (except the new EGPWS on the 737-800/900) not prevent CFIT in landing configuration.
Like Cisco, I also don’t think that the VOR approach for RWY 28 in ZRH is especially difficult. However, ATC usually vectors you around for a long time at low level, which could easily ice up an aircraft pretty bad in yesterdays weather condition. The long initial sequence of the standard approach (which you usually have to fly) doesn’t help either.
My deepest sympathy to everybody involved.