didn't Goodfellas enjoy a certain notoriety over its violence?
i'm not an expert
but in The Godfather they show you killings
in Scarface they show you torturous killings (the chainsaw)
in both of cases it's part of mob life. people getting whacked
in Goodfellas they have CASUAL violence
it's done spur of the moment (killing Bats for disrespect, shooting the waiter)
it's nasty (the stabbing scene, beatings...)
and it's really an extension of Tommy's PERSONALITY, not of mafia operations

it brings an element of terror to a lighthearted film
the casualness, combined with the volatile tempers and graphic depictions
it also makes the violence/mob more human

when they actually do have a mob killing, it's Pesci getting set up and whacked, and it doesn't even show you what happens, he just goes "oh shit"

*shrugh* maybe it was all done before