While there were worse bosses, Vito Genovese and John Gotti were really instrumental in blowing the lid off organized crime and allowing law enforcement to build cases, hand out indictments and in the latter's case, use RICO convictions to dismantle rackets entirely. Both of their leaderships caused major blows to LCN and even if they weren't the worst (they're admittedly well known and fascinating to study), their successors should not look at their reigns as a net positive for the mob.