I've changed my proposal from a several yard halo to 10 yards. If the ball travels 10 yards, it can't be intentional grounding. I understand the spirit of the law. So to avoid QB's spiking it at the first sign of pressure, make them decide whether unloading one down field is the better option. A guy under serious duress can't just wing one, and if he does, it's likely with some consequence.
In fact, I'd favor THIS version of the rule even it means the spikes Orton threw to his running backs' feet last night--again, with the BLATANT intent to ground the ball to avoid pressure, while standing in the pocket--would then become illegal.