I think it's the Garrett factor (which we still see with Kellen, his disciple). Garrett put together some pretty good offenses with personnel that was better than it will ever be given credit for being because it was held back by Garrett's offensive philosophy.
The problem with a Garrett-led offense is that when it goes up against high-quality defense, it doesn't have the innovative qualities to give it an edge. Moore has been better about that than Garrett, but he seems to revert to that less-creative philosophy at times, which leaves you with my 11 guys trying to win straight up against your 11 guys.
This is why I wouldn't mind moving on from Moore. He has shown he can put together a top offense in the league, but may just lack the ability to take it up a notch when needed by thinking outside of the box. Instead, there's a tendency to revert instead of innovate IMO.