pro: Maul being "Jedi" and turning against his fellows - Obi-Wan guiding him
con: Maul being "Darth Vader" from start - I think "Vader" should be either his name or a monicker, the "dark lord" later adopts
some things could/should be left in shadow, to slightly confuse viewers, as if OB1 or others seem to mis-remebmer or even lie about the past ...