Hester wasn't wasted at Miami, he was just a dumbass that couldn't figure out an offensive playbook. DH was a talented returner, but anything that had structure or required any kind of study, he wasn't going to do well at. Also the reason why the classroom wasn't his cup of tea. Devin could improvise on a return, you can't improvise as a receiver. DH also was a player that pouted whenever he didn't get the ball, so he had to have his particular package. You knew that when he was in, he was getting the ball, so defenses could easily key on him.
It's not an accident that he was a mediocre receiver at the NFL level too. There are guys that are great at riffing, but can't read a lick of music. DH was that guy.
JT4 isn't even close to the talent DH was. JT4 is a good receiver, that on a normal Miami team would be a part of the rotation. He isn't Santana, he isn't Roscoe. He isn't that kind of dynamic, take games over kind of talent. He flashes, but lacks the will to be that guy. Then again, maybe if JT4 would have been forced to learn under truly talented coaches, he would have developed. Then again, he does pout, whine and quit when a coach dares to criticize him, so odds are he would have washed out under a good Miami staff.