Putting Bradshaw on Pat's level is obviously silly, but calling Bradshaw a game manager is simple ignorance (no offense meant) of how that Steelers team operated. Terry was a menace come playoff time, called his own plays, and was the leader of that locker room. Once the Mel Blount Rule was implemented halfway through his career he started slinging the football, the Steelers offense scores 35 and 31 in back-to-back Super Bowls, he wins MVP both times, and wins the regular season MVP in '78.
With that said, he did greatly benefit from a being in a fantastic situation. Put him on the 70s Patriots and he isn't making the HOF. But he was most definitely not just along for the ride. Compare the tapes of Bradshaw in Super Bowl XIII with Brad Johnson in XXXVII. It's night and day.