Despite UNM's lack of historical success, they have advantages that Utah State does not. They are in a major metropolitan area. They are the best team in their state rather than the also-ran in their state. The conference just got a whole lot easier.
If Bronco stays, his challenge is to really find a way to get his team to outperform UNLV, Air Force, and San Jose State. If he could do that, he could build a consistent winner in the MW.
The Group of 5's, which is now I guess the Group of 6 with the Pac-12's revitalization, all get one bid. So no matter what conference you're in, you're in the same situation. The MW just got a lot easier, and he was in a good position to take advantage.
Utah State is in undoubtedly a better conference. But Utah State is not ready to compete annually with Boise State, Oregon State, and Washington State. They are also at a disadvantage to San Diego State and Colorado State, so it's going to be a tough job and much steeper hill to climb in that conference.