In short, I hate it and think all the skills should be visible. It's hard enough to do well at this game, you shouldn't have to guess what hidden skills might be out there as well.
Yes, there is a hidden "physical" skill.It's not strictly good or bad -- you just might want some players who are physical, and some who aren't.You probably don't want a team of all very physical players. However, it's probably the easiest thing to get from looking at the boxscore page -- if they average 4+ fouls per game, they're probably very physical players.