Then, her death scene could be intercut with the opening battle - IMHO it would serve as a much more dramatic intro to Grevious. As it stands he just walks into a room, coughs, and then vogues for the camera. Anyone who hadn't seen the Clone Wars series would have no idea how badass Grevious is.
Alternately, it might work as a nightmare sequence or a Force premonition...Hell, why not include it in AOTC with Yoda when he's meditating on the future of the Jedi?