The Final Episode Ever?
With Episode III, Lucas knew this was the big final act to his Saga (well at the time anyway) and so far hed shown us enough to believe that when Anakin wound up in the suit wed believe the technology behind it. Now lets look closer at General Grievous. He hates Obi-Wan Kenobi, for reasons pinned solely on their unseen conflict in the Clone Wars. He has lightsaber skills but unless you venture into the 2D Clone Wars shorts you only assume its because Count Dooku has trained him (within a three year period!) and hes only just about kept together within his metal body, coughing and spluttering his way through life. Now we know his big conflict in the film is with Obi-Wan Kenobi but even with his status as General within the Clone Army, hes not really more than a henchmen for Dooku and the Separatists. For Obi-Wan this is really no more than a distraction but within the story their rivalry is bigged up and their final duel is played out as a big deal and not just a General vs General big deal but like it means something to Obi-Wan personally. After all their epic battle nearly sees Obi-Wan losing and he only wins the battle with a blaster. Now, take a leap of faith and tweak all of this slightly. Looking at the epic nature of Revenge of the Sith and all of its events, its not a stretch to imagine that Lucas wanted to bring out all the toys for this final act. Vader, Yoda vs Palpatine, the fall of the Republic. Revenge of the Sith is packed with a whole lot of all-out Star Wars action. So far, hed used different Sith to show us the path Anakin was taking to become Darth Vader, yet in Episode III, he used a new character plucked out of the air. Darth Maul was a very popular face in the prequels. Lucas had killed him off, like hed killed off other fan favourite Boba Fett but this time he had another episode left to bring back a fan favourite.