I feel like the assumption to "promote from within and keep the staff," while thinking nothing will change is a little naive. While I believe it would definitely be in Greeneville's best interest to keep the staff in tact, promoting from within might not be the way to go.
By promoting from within, there is a great chance that another coach or two will get butt hurt when they are not chosen and will move on, essentially breaking up the staff. I have also heard that there are a couple of coaches that absolutely refuse to coach at Greeneville if a certain assistant gets the position.
I think with Cody Baugh, you get the best of both worlds. He has the best chance to keep the staff in tact and will provide the offensive leadership needed to keep this train rolling. Also, don't overlook the importance of Head Coaching experience. We have no idea all of the little things that a Head Coach deals with on a daily basis and only experience being a Head Coach can equip you for this.