Something I wanted to do was see Maul survive and remain a threat in the later films, to the point where people can think that Maul is Vader, and perhaps retain some of the ESB revelation. The easiest way is to suggest that Grevious is Maul (though personally I think his look should be changed to something more halfway between Maul and Vader, otherwise he goes from acrobatic sith, to acrobatic robot, to lumbering cyborg, and that makes even less sense), but something I considered was using sound clips from Anakin in the Clone Wars for Maul's voice, as at least this sounds close to Anakin from the films without being the same. That said I do like Maul's voice in the film, just there isn't enough of it without voice acting.