It's not a question of who but a question of how. To just pick Mario strikes me as if the hiring manager (AD) is thinking (a) he's a "Miami Guy", (b) he knows the program and the area, and (c) we're comfortable with him. Not a lot of thought or effort going into it. It may work but it may not.
A real effort would consist of doing the hard work and being somewhat introspective about what made Miami work. What differentiated Miami from all the others. What about it's culture that made it happen. Then doing a gap analysis about the current state of affairs. The results of that gap analysis would identify the attribute needed to set things right. That would in turn define the search requirements for the next candidate. All of this should be done before you even consider a candidate.
Once you sense that thing are going south, you need to get your antenna's out there quietly looking for candidate that fit the profile you've already defined. If you don't do that, you tend to skew the requirements to match the candidate. Also, it's already too late to begin the search once you're forced to fire someone. At that time, it's a mad scramble, an arms race at the end of the year when everyone else is looking.
I read a article about Sam Jankovich that during his travels around the country to conferences and what not, he said he came across Dennis Erickson who impressed him. Even though he had JJ, he made a mental note that he was someone he had to keep an eye on. When JJ left unexpectedly, he already knew who he wanted.
I know that's an awful lot of work to do up front before there's even a need to make a hire but that's what it takes to be prepared and not look like a fool. If I'm the AD, I'd also begin the process for Larrinaga. Not that I want him to leave, but at his age, he's going to retire sooner than later. It's what wasn't done when Morris left. I'm not confident that Blake James is up to the challenge.