Well, just think about the number of times that an FE may have saved major problems, and that's only in recent times:
* When QF confused their computer during the landing and overrun at BKK, the FE would have been loudly advising them of their multiple oversights, immediately after touchdown, when something constructive could have been done about it!
* When the MD11 had that inflt fire, the FE could have been doing something about it prior to it getting out of control, forcing them out of the cockpit!
* Just now, when BA had that cockpit intrusion, the FE could have stopped him a long way short of the primary flight controls, preventing all of that incident!
* That -200 that crashed just after t/o from LTN a few months ago, that was a Classic, and you know what, the FE was the only crewmember who realized what was happening, but the Captn didn't respond to his insistant calls, and flew the aircraft into the ground, AI problem!
Just to quote but a few!