Personally, I think that Grevious being Maul would of helped Grevious not be such a throwaway villain. But no, in the end, Grevious being Maul doesn't really make sense. But as a whole, I don't think that Grevious made much sense, other than a cool character that would sell action figures and gotta have something new and cool looking for the final film. Personally, I think they should of just done away with the character and let Dooku live longer, and fill the role Grevious had. It would of gotten rid of a waste of a villian, and given Dooku the extra screentime he deserved. He was built up too much in AOTC and Clone Wars to just get beheaded in the first 15 minutes of ROTS like he did.