Monroville said:
(3) Making Grevious into Maul would give Maul "more to do" as well as:
(a) make the fight between Grevious/Maul and Obi Wan a little more personal - being that it would mean Obi having to face the guy who killed his master once again
(b) give further explanation to Grevious' lightsabre stuff (as in: he has the skill to operate a lightsabre much less has multiple sabres because he has always been a Sith Lord hunting Jedi between TPM and AOTC)
(c) would serve as a nice lead-up to what is going to happen to Vader (ie the Sith never throw anything away, or unlike the Jedi who believe in an afterlife/reincarnation, the Sith are athiests who believe in the here-and-now and use technology to prolong their physical life as long as possible - all of which would further develop the culture of the Jedi and Sith just by altering Grevious' appearance and name).

After this Explaining im starting like the idea of maul grievous.

How about Grievous has Red lightsabers?

With some dialogue changing and we have a new cool villain.

-Angel