What if we took the idea of expanding Maul's character even further? In The Phantom Menace we find him on the mission with Obi-Wan and Qui-Gon. He is not either of their apprentices, rather is portrayed as an ambitious jedi who received an opportunity to shadow and study under the two great students of Yoda. It is implied they've been on many adventures together. I feel this could be accomplished by inserting an actor as stated before and having him say a line every so often in between Obi and Qui-Gon's making him seem to be a part of the conversations. The Galactic Federation (a separate government to the Republic) is looking to take over the Republic, being controlled by a mysterious Sith Lord called Darth Vader, who we never see. There is a mystery as to who or what Vader is. On the mission at the beginning Maul gets separated or something and is presumed dead. Only to turn up at the end, revealing himself to be the mysterious Darth Vader, having turned to the dark side in search of greater power not found with the jedi. This leads into the duel and adds a ton of extra meaning and weight when he kills Qui-Gon. This also deals with the part of ANH that makes is painfully obvious Anakin is vader which is when Obi-Wan says to Luke "who was a pupil of mine until he turned evil." without making Obi-Wan technically have another apprentice, as Maul wouldn't be a full on student trained by Obi-Wan, simply a lower-class Jedi shadowing him.