The fact is that the jet sweep is incredibly easy to defend if you know it's coming or expect it. With Harvin, it worked the first time, then not so well after that. It's a play you kind of have to set up for it to work effectively, no matter who the ball carrier is. Last year, we went to it several times. If the DE and the CB stay home and set the edge properly, the play goes nowhere and is likely to lose yards. It is, after all just another form of a reverse play. If you catch the D off guard, you get positive yardage and possibly a big play. If the D is disciplined and stays home, you're lucky to get back to the LoS.
It wouldn't surprise me if we try it in the playoffs, but only because we haven't used it much since Harvin left. What we'll probably see is No-E, or other WR in motion behind the formation on a fake reverse a few times, and then pop the real one when they think the D is set up properly.
Strategy, guys.