AT it's core (and I'm not sure we've achieved this yet) I believe the point of making Maul=Grievous is to add depth to and strip away confusion about who Greivous is and why Maul disappeared so quickly.

There is a feeling among some that Maul died to quickly and easily. There is also a common opinion that Grievous in the movies (apart from his very different portrayal in those CW cartoons) came out of nowhere.

Further, niether of them get any kind of depth. But if Maul = Grievous, all these problems are solved.

I don't think it can work without a "reconstructing Grievous" scene, however.

I hope someone can set me right. Commander?