I think you are overstating the 'stops" on Parker. #1 he was injured. #2 Part of the reason why LeBron need to D up on Parke is that between DWade and Chalmers their on the ball defense at G was brutal. If you watch him, he was not in his shirt but rather he played off him a couple feet. What he did do was because of his quickness and length, widen the passing lanes. This forced guys like Leonard, Ginobli, etc to catch at say 22 ft as opposed to 18.
If you are 6-8 ish will good speed, quickness, fundamentals, can jump and understand the scheme you can guard anyone for a reasonable amount of time until the matchup is exploited. LeBron certainly falls in that category but to what you just said he is nowhere in the neighborhood of guys like Rodman or Metta World...