Scarfo had a guardian angel in that situation, Nicky Buck. Even if he didn't whack out Scarfo, that was just his way. Bruno was close with Mr Joe Rugnetta, who was much more prone to violence actually Rugnetta was the one guy in Bruno's admin who actually was closer to him than the new school guys. Caponigro was only named because he was a growing power and I heard once that Phil Testa went behind his back on hits. Yet after the old school like Joe Rugnetta died off, Bruno felt he had to name guys like this to appease the new school. Bruno once had a guy named Reds Caruso killed by Scarfo and Merlino because he slapped Mr Joe. They ended up shooting him, but Bruno had insisted that he specifically be choked. To me this shows some anger on Bruno's part that he would have that kind of hand in the slaying.

Anyway. My answer is Vito Genovese any time before Apalachin. The mob would have been on less shaky ground if he had never come back from Sicily.