Hey, now, there's no need to impugn my experience watching Trek. I've seen it all. What I'm saying is that McCoy in command would be either something like Commodore Stocker's experience in the chair, or it would be like Scott's or Sulu's. Scott and Sulu are trained and experienced in command, and so either watching McCoy in a "Galileo"-type would be like watching Scott or Sulu do the same, because they're all passionate, volatile humans, or it'd be like watching Stocker try to command - awkward and scary.
Besides, McCoy is not a line officer. Doctors don't command ships. If somehow he ended up in command, then there must not be any experienced officers around, so who would he be commanding? The computer?
You're seeing things from an 'in-universe' perspective, I'm seeing things from a dramatic perspective, where everything is possible if it serves the plot or the characters.