It's a valid criticism of JG (unlike most of the ones we typically see here at VN). JG is still too slow to throw the ball sometimes and still struggles at times to read the defense. He's improved this season, though, and the flip-side is that he's absolutely one of the most accurate pure passers in all of college football.
Chryst and JG are pretty even overall IMO, with Chryst being better at reading defenses and JG being better at throwing very accurate deep passes. The problem with Chryst over JG isn't even really a problem with Chryst so much as it's a problem with our O-line.
Our O-line can not run block. We're averaging like 1-2 yards per carry right now against quality defenses. You can't win games like that.
JG gives us a better shot at winning precisely because what you saw against Auburn; he can throw the deep ball and spread the defense. With JG, it at least improves the odds for our run game. Against Chryst, it becomes easier for defenses to simply shut down the run. If we had Stanford's offensive line, it would be a different story, but we don't. Therefore, I think JG gives us a better shot at winning, and we saw that versus Auburn.
But it's absolutely true that JG needs to read defenses better to be elite. It's also true that he had crappy QB coaching for most of his early career here, so he might continue to improve rapidly.