To be fair, I think that certain ground staff need to have specific training in aspects of handling the aircraft.
AFAIK this was scheduled but put on hold when PIA last changed their minds, so there would have been no suitable staff to handle a 777 at short notice. For the same reason, I doubt they could take a 777 on diversion. I would be happy to be corrected on this.
On another note, I noticed up at the airport the other day that the SOU flight also had an AF flight number. How long has this been the case?