The whole "secret" of Sidious' identity was more of a nudge wink sort of thing. The guy never intended for the PT to have any surprises. Lucas obviously never considered the possibility that not every body in the world who was going to see TPM had already seen the OT. If he had approached the PT without the idea that everybody knows what is going to happen anyway, then no doubt it would have been a lot better. The whole "well they are obviously meant to be watched 4, 5, 6, 1, 2, 3" argument is retarded, if it had always been intended to be watched out of order then they would not be parts 1, 2, and 3 now would they? Lucas bunged the whole thing up, that is the only way to work it.