I guess I don't see Iowa, NW, or ISU in a gimmick in the same way GT is. They aren't one trick ponies, like GT. All of those teams can both run and throw at times. And they all have decent defense. GT's defense sucked when it really mattered, and their passing game looked like cave men trying to harness fire.
I mean gimmicky as in Iowa, ISU, and NW don't get the type of players that the Texas' and Ohio States get. They have to run a scheme and run that to perfection in order to compete. It isn't "tricky" per se, but it still somewhat of a gimmick.