It's a position where few of them are good at everything. And also a position with a lot of deviation in what DC's ask them to do. Some need to be able to man up, some need to ballhawk deep, some primary run support, etc. In quarters-heavy schemes they need to be able to consistently make their read correctly in conjunction with the CB on their side if that's the call or run into the box at the snap if they're run support on that side, or drop and put a cap on the play deep.
Both Rapp and Scott are meatheads. They're SS types. We need a guy who can break on things with some anticipation to help squash that bleeding underneath.