I do think that Potions are a very different class of magic--I don't see a reason except perhaps for some magic control of the fire temperature or something that a Muggle wouldn't be able to brew a working Potion, if the ingredients weren't squirreled away in the magical world. So, in theory, yes... if Voldemort had permitted a Muggle to touch him, the Muggle could have made the Potion. The actual resurrection within the Potion, I took to be Voldemort's magic. (And I am a Peter fan of sorts and agree that he's an exceptionally powerful wizard... people do tend to miss that! It just didn't seem to be what he was doing.)

Charms and Curses and so on seem to be mental power channeled through whatever causes magical power, focused with the wand. A Potion--judging by Snape's disparaging remarks about wand-waving and so on--isn't really accomplished through those means.