I don't want to go about beating around a dead Bantha, but after reviewing the sequence of the transformation on DVD I discovered something interesting when viewing the scene in slow motion within chronological order. In one shot, we see Palpatine's face becoming the Sidious of the OT, followed by more lightning to the face. After a few close-ups on a conflicted Anakin, the camera focuses back on Palpatine, who is still in a transitional state but is lacking the details present in the previous shot. It is as if the Sidious face is showing through once as the lightning is interacting with the skin, and then fading away, and then finally breaking through again as the Palpatine face melts away and Sidious says he's too weak to continue. If Palpatine was indeed literally deformed by the lighting, why did his face go from normal, to Sidious, to semi-normal, and back to Sidious again. If the lightning wounded him, wouldn't the wounds stay instead of suddenly disappearing and re-appearing? Watch your DVDs, you'll see it. I have a few screen shots that I can provide to show you what I am referring to. By the way, both this and the regular Wikipedia article fail to make any mention of Sidious' strange voice after he rises from the window sill and before he puts on his hood. In the commentary, Lucas said he added synthesized effects to the voice to make the "true Sidious" drip a bit more menace. That's all well and good, but there must be a within-universe explanation for it.