Garcia has never and will never be a hard hitter, Khan just struggles to take a shot. I think he really missed his conditioning coach Alex Ariza and I think he played a big part in helping prepare Amir to deal with bigger shots.
He does have great boxing skills but Amir refuses to use them and instead tries to fight with a chin and with power that he doesn't possess. Instead of using his speed and size he always gets drawn into a war which turns his fights into a 50/50 affair because this is not his strength. The fourth round was exciting in that fight but only because he was so dumb. He could have easily taken that round as a recovery round and stayed out of the way but instead he stood in front of Garcia desperately trying to knock him out. That is the exact opposite of what he needed to do and he got battered. While he does this he will always lose fights to lesser skilled fighters like Prescott, Garcia and Peterson.