Sauron FILMED in ROTK.
Whether or not this makes the final cut or not, we now know for certain that Sauron was FILMED as a physical presence taking part in the events of ROTK. This came in from Dave:
“I used to flat with a guy in the NZ army, and when he was in the filming for the big battle in front of the gates of Mordor, Sauron was there fighting. I believe he will appear. I mean there is only so much you can do with a giant eye.”