I'm approaching it where I do not see Miller as a sure fire starter this season (debatable, but that's my realistic approach based on how UNH handles playing time). I know there are doubts but Chanter was coming into his own last season with an increased role. I think he is worthy of a spot in the bottom four defensively based on what little I know about the incoming group. I do not fear that his having the "C" is indication that he will be thrust into a top pairing role that he is not prepared for (I will say I would not be surprised to see the coaches try it though See: Gaudreault, Maxim; Smith, Kyle; and MacDonald, Collin).
I can see the idea of the "virtual redshirt" being a positive as well, but it does not sound like Miller is so far above his competition in the BCHL that he would not benefit from actual playing time in that league. In that case, I would think the full BCHL season worth of playing time would be more beneficial. It's a thin line to walk, UNH has a signed NLI in their hand which plays in their favor. As long as there is an understanding in place that prevents a decommit, I do not see an issue with it.
And yes, I understand the fact that 10 is not likely the number to start the season. Miller seeming to be staying in the BCHL puts us at 9 and Boyd is a question mark with his constant health issues. Either way, we went from having to play Joe Sacco at defense to having a bit of a logjam with incoming blueliners. If there are too many bodies and one of your players will accept a deferral without decommiting (again, not going to be Maass or Gildon) then why not try it.