Underneath his pleasant, compassionate exterior Chancellor Palpatine is the wrinkled, red eyed Emperor from ROTJ. I do not expect the audience will see Palpatine show his true personality until the third act of the PT.
I started this topic to discuss the different ways this event could transpire.
Here are factors that I think would enhance the scene or are necessary for it to happen.
For Palpatine to express this side of himself, he either needs to be EXTREMELY secure in his office (more so than I think he will be at the close of E3), or he is interacting with a character that either doesn't threaten to expose him, or is someone that he can trust. I don't think that he can simply step into the freshly dubbed Emperor's pod in the Senate chamber and begin hissing at his fellow politicians as he does when speaking to Vader in ROTJ.
The nature of the third film could also play into this revelation. According to Lucas it is primarily about Anakin Skywalker's fall from grace. The Anakin we see at the end of AOTC will most likely not be the Anakin we see at the open of E3, or the Anakin we see at the close of the film. I think that being involved in the war effort is partially responsible for the change we see at the open of E3, but his developing relationship with Palpatine is probably a major factor as well.
The changing of the gaurd could influence the nature of the revelation as well. It is possible that the Jedi instigate the rebellion against Palpatine. There reason for doing so may very well be because Palpatine has allowed the Jedi to see him for what he is, knowing that their only choice would be to turn on him when his popularity is at it's peek.
A Jedi (perhaps Obi Wan) confronts Palpatine and his appearance changes as well as his personality. Eyes glow red, etc.
The revelation of the fully realized Darth Vader is twinned with Palpatine's revelation to the audience. We see the two conversing and Vader's dark robed master lifts his head enough to see the face beneath the hood.
It could also be a combination of the above theories, or something entirely different.
Got a theory on this revelation?