If you can't properly make the shoulder roll work perfectly then you end up getting beat up. There is no halfway with that and these people were under the impression that they were a lot slicker than they were
Broner's shoulder roll is a shoulder lean, and he lean right into your punch. He be on the ropes looking like he's doing the Fat Joe dance.
Besides, Broner is flat footed as fack. He relied much on his power but at Welterweight he's only half decent.