Khan IMO is done at top level boxing

Definitely.

If he could somehow adopt the style of a counterpuncher, he has the reach and speed to make opponents miss and pay the price. He unfortunately doesn't have the footwork to do this, and given the fact he doesn't really seem capable of fighting on the back foot.

Khan is all about offense, ever since he turned pro. Even his defense is his offense (and he didn't copy Pacquiao, or Roach didn't teach him to fight this way...he has always done it). What makes his punch resistance worse is that he charges in/jumps in when he attacks, he never creates an angle off the first punch, whether it be a minor angle or not. He's very predictable in that sense. Which is also another reason why he can't really fight on the backfoot, his lateral movement and distance judgement is not great at all.

 

There was an interesting piece of commentary from Roy Jonez about how certain fighters can only go so far technically since they have the mentality of a "killer".

Anyways, Amir lacks the temperament to become a counterpuncher. Counterpunchers are patient people.

I can see him improving his counterpunching skills.