No, he really wasn't a gamble. If you can hang on and get promoted with an elite coach for 8 years across 3 programs and winning 2 titles, then you're pretty good. If there was anything we knew, it was that Mullen knew what a national title winning program looked like. People said the same thing about Smart, and look how he's turned out. So what you're looking for is a young coordinator who has time under an established winner.
So you might say, "well that's Arnett!", and you would ALMOST be correct. He's got about 5 years worth of experience under good coaches, and I honestly do think he's got what it takes to be a head coach. He just jumped the gun on a few things. He should be calling the defense still, and totally delegating the offense, then slowly transition once the next DC is ready. But either way he needed about 3-5 more years of seasoning, some need less, some need more. Oh well.
So who are some other guys that fit this mold? Well it looks like Dan Lanning is working out well, and he only had 3 years of DC experience. Mel Tucker was OK until he started spankin' it on the phone. I don't know who they are, but I'd be looking at Michigan/Ohio State's coordinators.
Bottom line is, do this, you'll get a solid coach, when in doubt. I personally think we need to go after a proven commodity this time around, we can't continue to suck. That's why I want Mullen or Malzahn