The NFL wants to have the crazy-seat-of-your-pants fun of watching a QB scramble all over the place and make a big play, but they don't want to see their QBs get hurt.
And while that makes sense from a marketing perspective, the laws of physics say otherwise.
So the NFL has decided to completely shaft the defense in general. I'm convinced that last season, had Kiwi sacked Vince Young, they would have called roughing the passer anyway....that's why that play didn't bother me much.
If they really want fair rules, they would say something like this:
1 - If the QB is in the pocket, and is grabbed, it's an instant sack....to "protect the QB".
2 - If the QB is outside the tackles (i.e., outside the hashmarks), and/or over the line of scrimmage, then for rules purposes he is no longer a passer, but a runner....i.e., roughing the passer penalties are now voided.