If I'm following correctly... Techster was simply originally saying that Hill has the overall physical gifts that equal some of the greats like DT and Calvin. I think we can all agree that he has the speed, jumping ability, and honestly probably is close to being as strong as those guys as well, but what others have mentioned he isn't as thick, so therefore he may not be as physical.
In my opinion, being physical probably doesn't have that much to do with the 10-15 pounds that he is missing from DT or Calvin. It has more to do with want to and mentality. DT will viciously stiff arm dudes back into their mothers wombs, and I don't think weighing 10-15 pounds more gives you the ability to do that, you just have to want it. Calvin would out jump and outmuscle anyone on every single jump ball. I think Stephen has the physical ability to do those things as well, but I'm not sure if he has the same mental drive that those guys have. It also hurts that he has butterfingers and serious mental hiccups running routes. Overall I just don't think it ever fully clicked with Stephen, which is unfortunate, because he has the physical tools.