Just looking at the numbers, his ISO has increased over the past two years or so. He was normally a ~.110 ISO guy and the last two years it has jumped to ~.165. His BABIP is way higher now too so he could be feeling the extra speed to leg out hits from the test boosting.
I know Morse stated the steroids he took were to heal from a lingering injury back when he was in the minors. Honestly I don't think its an apples to apples comparison and no PED case is the same. Competitive advantage or not, Melky always had a pretty good eye so maybe the extra muscle was to help all those bloop hits happen. Who knows besides him? Maybe if he didn't even do the drugs, he might have still been a damn fine ballplayer, maybe not a batting title champ but seriously he could have been a good ballplayer.
He'll be back next year and no one will really care. See Braun, Ryan.