yes, fatigue is a major problem. but having a super jet that has enough nav capability to tell you where you are all the time may have lead lead us down the garden path.
in the old, old days, vectors were provided to intercept the GS from below, and a check was provided at the OUTER MARKER for crossing altitude.
in the rip roaring days, vectors were provided and sometimes you intercepted the GS from above and forced the plane onto the GS but still checked at the outer marker.
WE are asking too much of everyone, lets' go back to the old days...it might require a tad bit more fuel.
Perhaps plane trips are too long and even relief or augmented crew members should be replaced by multiple legs?
if fatigue is a problem multiple controllers and absolute radar monitoring of approaches must be req'd.