About Lebron's defense, let's get real.
Is he versatile? Yes. But he can't guard every position well he just can guard at every position. He might get to guard the Andre Millers and Raymond Feltons of the world on occasion and say he is defending the PG position but you don't see Lebron guarding the Chris Pauls, Rajon Rondos, Steve Nash or Ty Lawsons of the world. And he might guard some centers but he's not regularly guarding Dwight Howard or Brooks Lopez or Marc Gasol or Tim Duncan.
Also, the officiating makes a huge difference. Lebron is protected. It doesn't matter what end of the court he is protected on because his lack of fouls being called, whether in the offensive end, the defensive end or the loose ball variety means he gets to play without having to worry about picking up fouls. It makes a huge difference.