Well, for starters, I don't think his DC needs to have experience at that position so much, because Pruitt (an experienced DC) will have a lot of say so on that side of the ball. You may have a better case on offense.
My optimism comes from the fact that he seems to have a plan, and has so far been able to implement it with very few hickups. He seems to be getting what he has wanted on his staff, and I think recruits are listening to him as well.
He has apparently told two QB's that they can find another place to play. Some may see this as a bad sign, but again, I think he has a plan and is confident that he can make it work.
He appears to be cherry picking staff from other SEC schools, which has it's benefits, including the highly regarded GM from LSU.
He also appears to be laying a foundation of having more support staff than TN is accustomed to having. This is the Alabama model, and if we want to compete with them, we may have to start with mimicking them in this area.
All this may be for naught if he fails to change things with Strength and Conditioning, or if he cannot teach the players or implement a good game plan. However, all we can go on is what he has done in one week, which I think is cause for lots of optimism.