I don't only do SEC, and I have looked around at other coaches more specifically. The list of coaches that people see as being great, at one time or another, but who really don't perform all that spectacularly in relation to talent is pretty long.
Examples:
Malzahn.
Chip Kelly.
Pinkel.
Meyer.
But, there are those that tend to stand out in relation to talent for significantly over-achieving.
Petrino (at Arkansas)
Spurrier (at SCAR)
The problem is, the coaches who do have a long run of significantly over-performing also have some major flaws. First, they don't tend to recruit well long term. Second, while they do tend to play the role of giant killer well, they don't have the horses to truly compete. Third, they tend to have an arc from inception, to peak, to flame-out, that is pretty repetitive.
To answer your question about Snyder, I'll let you look for yourself (I ran a quick visualization for you).
View attachment 111158
His performance in relation to talent, Snyder is certainly one of the best. Since returning in 2009, he is averaging about 5 games a season over expectations. But, he has the same inherent flaws as other coaches who over-perform. Namely, he doesn't recruit well. And, in Snyder's case (opposed to either Petrino, Spurrier, and others) he plays in a conference that is relatively weak. Understand that as a general statement, the meat of the Big XII are less talented teams than the worst of the SEC. That doesn't mean that he also isn't performing the role of giant killer well (namely beating the best talented teams in his conference relatively frequently) but he is doing it in (generally) the middle of the road in terms of talent in all of the division formerly known as 1.
As I mentioned earlier, the further down you go on the talent list, the less stable the predictions tend to become. I surmise that part of that is when you get to the middle to bottom tier teams, that the roster trends more towards 0-3 star players instead of 3-5 star players, and I believe that recruiting services don't know how to differentiate the bottom of the talent pool as well as they do the top.
The point is, that while what he is doing is hyper impressive, it won't lead to true long term success, or to a legitimate shot at titles (though, he will rack up a lot of wins with a very limited roster).