Strong Safety is a very skilled position. Gotta be able to cover, then you have to be able to provide run support. It takes a lot of skill to know when to drop into coverage or know when to show up on the line to support the run. I imagine a lot of keys to read, running backs, slots, tight ends, and even tackles and guards. The physical aspect is huge as well. Can't have a 5'9 - 180 pound guy at the college level covering 4.4 receivers, 6'5 tight ends, and also ready to take on a 230 pound running back or 330 pound pulling guard or tackle, but also know a 6'3 - 230 pound guy can't keep up with the speed in coverage most times. Isaiah Simmons was one of the best I have seen to do this. I don't even know what position they tagged him with, but he was a perfect strong safety. Shows, because he was a Top 10 pick in the draft and will be a major asset for a team with his ability to do what so many others can't.