I'd be happy for it to work. Lord knows I've suffered enough watching Lacrosse schools beat UM at noon on ESPN3.
A few challenges stick out:
We would need a TV deal to justify the exit (like NBC and ND). The market seems over saturated as it is, and its not clear what extra sizzle UM would bring. This leads to the next point, regarding the potential customer base for such a TV deal.
We don't have the slavish devotion of generations of former altar boys and cirrhosis-ridden Micks like the Domers do.
We don't have a favorable social/political immune system like schools in the deep South or the child r@pe factory in Pennsylvania. That sort of ecosystem acts like an important buffer to protect schools when a conference will not. In its place, we actually have a viper's den of self-interested chodes like Le Batard and Luther Campbell who would sell their own grandmothers into Chechnyan human trafficking for a cover article in the Miami New Times.
Regardless---and this is probably the most crucial, fundamental challenge---such a move would require a degree of competence, coordination, and organization that does not exist at UM (really, in the entire state of Florida).