I know telling developers to "make X interesting" or "make Y good" is a bit much; but for Mafioso it had to be done.
Mafioso is literally the most boring role in the game; all he can do is claiming vet/vig* when asked and waiting for his eventual downfall.
Mafioso's night ability isn't even a true ability; its just Mafia's "kill button" as a whole. He cannot even decide on its target; because it isn't really HIS ability to use. GF has control over him.
All those other roles can pull some cool tricks, yet Mafioso is like... okay...
Too many people instantly quit after seeing their role as Mafioso, unbalancing the game and ruining it for Maf and Neutrals.
I personally dont quit as a Mafioso, I try my best regardless; but people apparently just don't want to stick with Mafioso.
*(I personally experiment on various other role claims to some success)