If you can tell me how Steriods improve hand eye coordination and natural talent as it relates to a fluid and almost flawless swing, I will change my tune. Lots of guys out there on the juice that couldn't duplicate Manny's swing.
Also, if Manny Ramirez was facing juiced up pitchers (which he was), they cancel each other out.
Sure steriod, give guys an edge, but if it was all the drugs, you'd have a shitload of guys with numbers/talent like Manny, and we all know that is not the case. Many is one of those rare cats that was built to hit a ball with a bat.
I'd say at least 70% of MLB players were on shit when the "steriod era" was at its peak.