keygrip,
many ways to skin a cat so they say. Ok, lets make up a senario. student flying in the circuit, engine problem occurs and the student takes a few seconds to establish that there is a problem. in that time they have possibly descended 200 feet which make it pretty unlikely they are going to make the airfield. so what should they do? well if you had flown some pfls they would at least have some idea to turn into wind, get best glide speed and attempt a landing in a field. maybe they would even remember to turn of the fuel etc...
if they dont fly at least one pfl then they would (i believe) have very little chance of making a safe forced landing, on or off the airfield.
as per navigation, no i dont teach this prior to solo, but i do try to cover most things. i make sure they have at least 3 hours endurance in case the airport should have to close and i tell them where other airports are and what they should do in an emergency like airport closure.
no you cant cover all possibilities, i never said you could.
and what exactly is a standard pfl?! i teach pfl's from various heights as its unlikely they are going to occur at one height!