We already know where Maul's story ends in Rebels, he dies consumed by old hatreds on Tatooine. If Shadow Lord had shown him actively trying to change and fail, or choosing to walk away from Devon to spare her, his ultimate downfall would feel even more heartbreaking. Instead, by having him orchestrate Daki's death, the writers just turned him back into a another Palpatine, which feels regressive for a guy whose entire identity is built on hating Palpatine for robbing his life away.
The show gave us a glimpse of a deeply complex, emotionally intelligent anti-villain, only to sprint right back to standard Sith villainy.
His relationship with Devon is just kidnapping and coercion and manipluation from Maul's side and plot device Stockholm syndrome from Devon’s side. 0 chemistry between them. Maul has a stronger relationship with Rooks than his ideal apprentice. Could have had a nuanced father and daughter dynamic like Arcane. But nope. Maul is just Sidious and that's it. He can't and won't try to change. That just flats Maul, not flesh him out more.
