I'm gonna go a whole different route with this because I view the whole arc differently. The last four episodes are considered an "arc" by the show's creators. If you look at it that way, and I do, the story isn't about Maul at all... it's about Ventress. She's the only character to appear in all four parts (albeit briefly in the third) and she provides the key to the climax... beside which, the main drive, story-wise, is that she undergoes character development to the extent that by the final episode she makes choices and takes actions that she would not have done in the first, or ever before. Looked at that way, Maul is sort of just the "superweapon of the week" and could be easily replaced by any other plot device. That's an overstatement, of course: a great deal of narrative time and exposition (to say nothing of OOU hype and hoopla) went into establishing that Maul is back and positioning him as a major player in the show. But really, the main thing he does for the story is the ensure that Obi-Wan is drawn out at the same time that Ventress tracks down Savage. The brothers are essentially there to engineer Ventress and Obi-Wan hooking up now that she's changed a bit. For the record I find Maul's resurrection pretty dumb, but I'm not that interested in an endless discussion of it because it's happened, and no amount of carping about it will undo it. What they've done and will do with the character is another thing... if it had been thoroughly awful maybe I would've been done with the show. But as it stands we have the potential for an interesting new faction in the war (the brothers would be stupid not to totally mobilize the Nightbrother clan, right?) and what strikes me as a very interesting new lease on life for Ventress, who's been one of my favorite characters from the start. So I'm still in.