A 411
As you have stated, I have also seen some low hour F/O doing just fine as you did, as long as all is pretty standard.
As soon as you get out of the standard profiles the low hour F/O can get lost very quickly.
Usually you can see it happening miles from touchdown. The fact that the B 707 was a conventional plane as opposed to the nowadays FMC equipped acft is to a certain extend to the disadvantage of the pilots being trained today.
On a two man cockpit long haul, fatigue can be a serious factor and you really have to have a lot of hours under your belt to be able to anticipate.
As Boeing has stated when they introduced the B 777 around 1995. “This aircraft needs a crew with very high experience” I think that Malaysian Airlines have just proved that in Zurich.
I think that today there is truly a shortage of pilots with 6 to 7000 hrs command.
Cheers