Ian delivers some of his best stuff in ROTS (the opera scene shows a very surgical claw in a velvet glove) but as soon as the Halloween mask is glued on he becomes really silly and we didn't need it.

Lucas clearly thought that if the Emperor didn't look exactly the same as he does in ROTJ we would be too stupid to recognise him and while the Emperor is a bit of a smarmy git in ROTJ he doesn't act like some demented muppet like he does in the last act of ROTS.

It would have been so much better if they ran with the line Palpatine was spinning in the opera scene of him revealing that he isn't what he seemed to Anakin but also planting the suggestion (with some foundation) that the Jedi Council aren't either and then have Anakin put them to the test.

This would turn Anakin/Vader into more of a nihilist villain (he has lost faith with the ideals he once had and lost trust in the authority figures that surround him and wants to punish their hypocrisy).

Not only would that explain his attempts to destroy the Jedi and his suspicions about his wife but also his plotting against the Emperor too.

His redemption in ROTJ would have then been his reconnect with the idealism he had as a boy.

Gods, why didn't Lucas get a proper writer in (not to mention a more solid core cast of actors).

With all that prep time between 1983 and 1999 (not to mention the three years between each of the prequels) he could have given us something really special instead of worrying about if the CGI was up to scratch.