Maul was not the only inspiration for the Assassin class. Probably a bigger inspiration for the class was Darth Bane's apprentice Darth Zannah, who did you stealth, force clock, a double light saber, lightning, and many of the talents like haunted dreams under the Madness tree in the books. She is the only sith to ever sneak into the Jedi Temple, that I knew of when I was heavy in to the extented universe.