Ringer Spy Bregedalagos, who is new to us, and therefore cannot yet take everything a red, sends this in. So take this all with a mountainside laden with salt!
I managed to find some very interesting Return of the King spoilers info from a source very close to the film. Mainly, it regards the seige of Gondor, and events closely related to it.
When Denethor is on the pyre, burning, we see a closeup of the palantir that he grasps, and in it, we see a flash-ahead to the destruction of Barad-Dur, and the Nazgul falling in flames. Gandalf is there, as well as Pippin.
Gandalf says to Pippin, “Sauron could not conquer him like Saruman, but he concealed the true hope, and so Denethor was deceived.” In response, Pippin says, “None of us are safe then.” Gandalf’s response is “We cannot be truly safe while Sauron rules.”
Shortly after this, Beregond comes in, and sees Denethor’s body. He simply says, “Such a waste of one so strong against the East.”