Actually, most current SEC coaches had less HC experience when they took their jobs. Maybe all of them outside of Pinkel.
Don't discount the value of being a coordinator at a high profile program, which almost all of them were.
In fact, Butch's career trajectory is unusual in that he has no high profile coordinator experience at all. He was in a small pond for a significant number of years during his coaching career. Two seasons at WVU as WR coach were the extent of his P5 experience until he was hired by Cincinnati, and even then he only spent three years there (and it's not exactly the big leagues).
Look at the other mid-major guys who received/are about to receive big-time jobs.
Charlie Strong was DC at UF. Tom Herman was OC at OSU. Kingsbury was OC at A&M. Fuente was OC at TCU. McElwain was OC at Bama. Even James Franklin was OC at Kansas State and Maryland before getting hired at Vandy. Those are important years for future head coaches.
I would argue that Butch's three years at CMU were less valuable for him than being a coordinator at a major program for the same length of time would have been.
Butch is the definition of a CEO coach. He's a motivator, he's a recruiter, he's a team-builder. But he's not much of an Xs and Os guy, and that's why we've struggled a bit during his first three seasons. He can't just outscheme the opposition on a weekly basis. He has to rely on getting his players to play over their heads.
It will be interesting to see how he does when he has a talent advantage over almost every team he plays. He has yet to lose a game against a team that he out-talented by any appreciable margin (and Vandy 2013 doesn't count, considering all WRs were hurt in that game and Dobbs was the 4th string QB).