I think it is an insightful consideration, and definitely a different perspective from what we have heard over the years since it was revealed. Father's theories are noted in red of course.
After the two parts which I have already explained, at the left of Our Lady and a little above, we saw an Angel with a flaming sword in his left hand; flashing, it gave out flames that looked as though they would set the world on fire; but they died out in contact with the splendour that Our Lady radiated towards him from her right hand: pointing to the earth with his right hand, the Angel cried out in a loud voice: ‘Penance, Penance, Penance!’. And we saw in an immense light that is God: ‘something similar to how people appear in a mirror when they pass in front of it’ [It could be a reference to the Pauline image of seeing through a glass, "darkly". Some might be tempted to think of an image on a television screen or monitor.] a Bishop dressed in White ‘we had the impression that it was the Holy Father’. [Benedict is now just a "bishop dressed in white".] Other Bishops, Priests, men and women Religious going up a steep mountain, [Granting that it was the 2nd Sunday of Lent and the Gospel was the Transfiguration, in his final Angelus address Pope Benedict said" "I feel that this Word of God is particularly directed at me, at this point in my life. The Lord is calling me to "climb the mountain", to devote myself even more to prayer and meditation."] at the top of which there was a big Cross of rough-hewn trunks as of a cork-tree with the bark; before reaching there the Holy Father passed through a big city half in ruins [The papal gardens at Castel Gandolfo contain Roman ruins from the time of Diocletain.] and half trembling with halting step, afflicted with pain and sorrow, he prayed for the souls of the corpses he met on his way; [...] - WDTPRS
Fr. Z appears to be among those who think there may be another part of the Third Secret not revealed. Cardinal Ratzinger, Cardinal Bertone have said that the entire secret has indeed been revealed. I accept them at their word, and believe the entire secret has been revealed. Remember, the Third Secret is really just the third part of the entire secret of Fatima. The essential part of the secret was known for decades, and that was Our Lady's intention - put all three together and you have the text and the vision. The third part never needed to be made public - Lucia intended it for the Holy Father and left everything to his discretion - even the interpretation of the vision. Blessed John Paul II made the decision to make it public. That said, we know exactly what we need to know: Repent!
Speculation is simply entertainment. Just like trying to guess who the next pope will be.
Sadly, modern locutions and apparitions often seem to foster suspicion and mistrust of the clergy and hierarchy in their wake.