2 crew is fine for normal operation. But get a tricky emergency and a complex checklist and you suddenly wish for a third crew member.
1 to pole the aircraft.. .1 to handle the systems and checklists.. .1 to communicate, with ATC and Cabin.
Trying to handle the checklist and the radio can be a mare, every call interupts the checklist.
If the automatics are available, I prefer to hand off the radio and flying to my colleague.
If there is a third pilot on board, even if not on the same fleet, I brief them to be prepared to take over the radio in the event of a major emergency. Might as well make the jumpseater earn their place!
So, in an emergency I'd love to be able to teleport a third crew member on board, pilot or F/E, either would be great.
Would a third crewmember be good? Yes.. .DO we still need flight engineers? Not as such.
CPB