^"Good luck, you're gonna need it".
If you could do it, it would be a valuable resource (like the Fettless ROTJ) for people who don't necessarily want to remove him entirely but want to change his character.
It would be interesting to see how and indeed if the film works without him (he has a lot more screen time and interaction with the major characters than Fett does in ROTJ).
Ady wants the first two prequels to be Threepio free.
It looks like by the time we are all through Star Wars will be a series of nice backgrounds with no one in them :-D