I share some of your concerns but Im not in agreement with much of it. I have little or no concern for the students having to drive across town to see a game. UM is Miami's team, not the team of a small handful of the fanbase. UM has ~10K undergrad students. If every single one of them attended every game that would not mean too much for attendance.
We're not a college town. Hence UM games will never have that college town vibe. That said, UM tailgates tend to have an epic flavor that you cannot get anywhere in all of sport. Yes some of that includes the student tailgate section, which has NEVER been close to campus.
UM played in the Orange Bowl for 70 years and no one ever complained about not having an on-campus stadium. Field a competent team consistent with historical UM standards and the stadium will get filled. Hard Rock is a pretty **** good stadium. If there is one concern with Hard Rock its that they've been taking away the tailgating areas for formula one and tennis bulll****. That might be a valid reason to look elsewhere. (as noted by
@TheOriginalCane )
In short, Im torn on the stadium idea. Again my fear is that they'll build it too small and it will not have that big game feel. I saw it out here when Stanford did it with both football and baseball. They downsized Stanford Stadium from 85K to 50K and they downsized Sunken Diamond from 5K to 1500. I would hate to see UM go that route.