A pedophile/rapist gimmick would only draw "change the channel" kind of heat. He'd been gone faster than Muhammad Hassan was.
I think it would be cool to have someone on the show who once killed someone. In self-defense, that is. Like how New Jack killed some people in real life and how he had a bit of a mean streak back in ECW and had his real-life justified homicide to back it up (I'm guessing, I never watched ECW, just going by what I heard.) Well, say some guy was attacked and ended up in a fight with someone and ended up beating them to death or something (maybe there were two people who attacked him and the other guy is still in the hospital in critical condition or something.) That shows he has a mean streak and is a bad ass not to be messed with in the ring.