And then there's Palpatine, who was definitely not killed off too soon or in an unsatisfactory fashion, and nobody was wishing to see more of, but we got him anyway.Boba Fett's demise was very unsatisfactory.
But not Maul's. His screentime was too short, but his battle against Qui-Gon and Obi-Wan in The Phantom Menace was some of the best Star Wars ever done, including his two pieces falling down that shaft.
We needed more Boba Fett AND we were upset over how the Sarlaac ate him. Maul got a good ending, but we still needed more Maul because he was so menacing and cool. Irony is, IMO, the resurrected Maul ended up a very different character once fleshed out in "Clone Wars" and "Rebels". Still awesome, but not quite the savage, mysterious, menacing Sith Lord from The Phantom Menace.