they play different positions that require different skill sets.
bLUE.. SS more of a run supporter........FS more of a pass supporter. Sharper played both, which is why his IQ is higher, and do you honestly think if the Saints got rid of Harper teams will be breaking their necks to sign him. The only highlight they will probably show is him getting sucked up by Sam Bradford and nearly passing out.
Again two defensive coordinators coached top 10 defense sin the nfl, yet when they coach the Saints defense, their defense ranks near the bottom, the common denominator is the players. I would have rather seen Harper take Shanle's place at lb, that way he's not exposed to too many passes, and at least we won't have to worry about him covering wr's and te's.