On the whole lightsaber issue/problem. Had a sort of wild idea; could Anakin give Obi-Wan his lightsaber the last time they see each other before Obi-Wan leaves for Utapao. Instead of Anakin saying "Your going to need me" - Could it be changed to "you might need this", and then move into a close up of two hands with the lightsaber changing hands?
Just a thought... It could also mean that he already has a red blade when he cuts Windu's arm off. Would possibly change the perspective of Anakin turning up at Palpatine's office that he had already decided to side with Palpatine and made himself a new saber.
Just a thought...