After the battle of utapau, if Obi wan hadn't killed Grievous. Lets just say Grievous had escaped, with the rest of the movie playing out exactly the same. Would Grievous have survived. Would Palpatine have had a spot for him in the Empire? Maybe to help kill the remaining Jedi? Or would he have just got vader to get rid of him? What do you think?
Grievous was disposable. I'm sure Palpatine planned either to simply let him die at the Jedi's hands or personally double cross him after acquiring Anakin.
I think that Grievous was a better villain than depicted in ROTS. He was very disappointing in the movie. His cough threw me off completely.
Palpatine no longer needed Grievous. In order to control the Senate and permit a smooth transition into the Empire he needed to seem like the hero who was able to destroy/defeat a war hero like Grievous. He would've simply had Anakin destroy Grievous to make him look like even more of a war hero.
No arrest for the Chancellor with GG on the loose, so the film would not play out the same... at all.
Now that would be a cool duel. And I agree with the notion that Palpatine wanted to tie up any loose ends with the Separatists when starting new with his Empire.