Amuso and Casso were probably the worst boss/underboss combination of all time. I wouldn't say it was because they were young, more because they were complete paranoid psychopaths who should've never been anything more than capos.

I'm surprised Corallo chose Amuso as his successor, you would think he would've made a better choice. They didn't destroy the family though, seems like Crea has stabilized them since taking over.