Why would you need to fly the route in a real aircraft with different winds and conditions ?
A simulator would be far better as the winds and conditions could be loaded to match the conditions on the day!
I would also add i am sure this has already been done in a sim many times to date. Agreed. And the simulation would be better. They know the exact fuel load,where the freight was loaded in the holds, the a/c all up weight, a reasonable idea of the weather and more importantly very detailed history of that particular airframe and its engines' performance.
Well, if the point was to validate the satellite track data then the simulator is of absolutely no use at all is it and I believe that was the point of this particular suggestion.