Why? I like the idea of the DC having no position to have to focus on during drills/film/prep where he can move around and coach every part with no distractions. Probably part of why Heacock is so great.
Because if I'm Mickens/O'Leary/Washington, I don't want another coach stepping on my toes.
As far back as I can remember, Notre Dame's DC has always coached a position and it worked out well.
And isn't an official coaching staff limited to 10 coaches? Idk how that would even work.