Can't say someone is the "least qualified" just because he's been there the least amount of time. Whatever it takes to make a great head coach isn't measured in 'service time accrued.' Experience may be a part of it.
We can't know which of our assistants stands the best chance of being successful. I think everyone assumed Hopkins had 'it.' IMO, 'it' depends on context and situations. The same coach can go to Washington and have ups and downs. He could have gone to Duke or stayed with us and been great. JB himself might have been 'nothing' had he taken some other job.
I expect the AD will try to weigh and factor in a great many criteria. Natural intelligence, game/basketball intelligence, passion, innovation, dedication, creativity, command, personal character, 'salesmanship,' culture-building, aura, presence... lots of characteristics, traits, and skills, and few of them have anything to do with seniority. Being a great recruiter might be a skill limited to only that one facet. Being a good teacher may be a skill limited to that one facet. I hope we get someone who encompasses most of these, but it's going to be a guessing game—and a greater leap needs to be taken if the next coach doesn't have any HC experience, but even if he does, it won't have been under the same circumstances as he will be entering.
I agree that we need to scour the field to find potential candidates. But, every time someone says that 'it's stupid to just hire an alum,' they don't really post a suggestion from the outside world. As an ideal, of course we have to consider an 'other.' But, that comes with risks, too. That their 'dream job' still might be elsewhere, for one. It would not be fun to have to go through this again after 4-5 years, just because the next guy gets to a couple of Sweet 16s and his alma mater suddenly has an opening and a lot of cash.
GMac may, indeed, be the more talented coach from our current bench. It would kinda suck—from an 'appearances' perspective—for him to leapfrog Red. But, if he's the choice, i hope it's because the AD has the assessment skills to recognize that he has the 'stuff' to do the job. I'd almost rather see that happen than just to rely on seniority as the primary factor.
If you favor an outside hire, can you imagine how you'd feel to read that all the current staff had been let go and we had only 'foreigners' on the bench? As much as i want change for the program, i'm also not cool with having the axe fall on everyone.