[member="Connor Harrison"]
For me it's a more along the lines of "about damn time!" Ever since he returned in Clone Wars, and was still alive after it ended (and still wouild've had the show remained on air) it was pretty clear that if Maul were to ever show up again, it would be to end things with him tracking down Obi-wan and as Maul puts it "ending it where it all began" for him. And that's what his appearances in Rebels has been building towards.
Now that Maul has appeared in Rebels, there's no way he can still be alive by the end of the show. He falls in the same camp as the main cast (or primarily Ezra and Kanan) in the fact they really ought to not be still alive when the events of A New Hope come around. Which I think Season 3 is about 2 years before. Albeit with Rogue One we know at least one member of the main cast is still around as well as their ship as they participated in the Battle over Scariff
Ultimately though it makes sense why if there is ever a Obi-wan anthology film, Maul would never show up. It would make no sense to the general audience to have him suddenly appear when the last time he was seen for many, was in Phantom Menace.