I think a lot of fans are apprehensive because Mike more or less failed as a big time DC at OU, and could find himself getting the role here when White moves on. Stoops loves promoting from within the program. If he can help with game planning, firing up players, recruiting, ILBs, etc, then great. If CMS promotes Mike to DC, we may have some issues.
Tons of experience or not, the dude hasn't been particularly successful when compared to brothers Bob and Mark - even when coaching under them.
I hope he kills it. I'm just cautiously optimistic, and I think a lot of folks are as well.