I went to Catholic Schools for 12 years. Started in 1968 - through 1980. During the late sixties and mid-70's - our nuns wore the strict black and white habits. Some were kind of mean. Most were wonderful. I wouldn't trade my experiences for anything! I guess I was one of the lucky ones who attended good schools.
I would say, however, that the sexual abuse is so much in the spotlight now - and there is so much focus on it - that I don't think the abuses are anywhere near what was going on in the past. I would bet that the incidents of abuse are no more than what you would find in another large institution.
You ask about the deviant behavior? I think the answer lies in the Church's insistence that the clergy remain celibate and single. I think it goes against the very nature of man.