I don't know who pioneered EPO use for athletes in general, but Dr. Ferrari was the one who pioneered it for UCI pro cycling. He was working with a number of teams before Armstrong commandeered him for US Postal.
Not everyone was doping, at least to the level of US Postal or Festina, but if you didn't do what Lance told you to do, he would destroy your career. He was a total prick of the highest order. He abused everyone around him. In my mind, that will always be his legacy. He put riders lives on the line so he could win without any regard for their safety or well being.