Originally Posted by Fealiks
not true, George Lucas wanted palpatine to do all of it. although the actor is, as MacLeodCorp said, crap at swordfighting, most of the shots shown palpatine's face. George realy wanted the audiance to realize the anger and facial expressions in his (palpatine's) face.
No, Ian McDiarmuid did not do all of it, they talk in depth on the special features of the ROTS DVD about the whole sequence and the stuntman used in place of Ian.
Of course it was Ian in the more closeup shots in the fight but I'd say half of it is the stuntman. You can clearly see that the actor is not Ian when Mace disarms Palpatine and he crawls quickly to the corner of the windowframe.
Don't go around trying to disprove someone unless you know for a fact that what you are saying is true.