It takes more than just a good head coach to win championships of any kind. It takes a staff full of good coaches, particularly at the coordinator level—and particularly in the spot opposite what the head coach's background is.
I don't think it's possible to win a national or an SEC title without great guidance on both sides. Maybe the coordinator who does the same thing as the head coach is fairly anonymous, but the other one shouldn't be. It's not that you can't win big without a big name coordinator, but rather that excellent work will inevitably make a coordinator more well known.
Tennessee has had fairly anonymous coordinators under Butch Jones. I doubt many non-Volunteer fans knew former OC Mike Bajakian's name, but Jones has an offensive background. Current OC Mike DeBord is more well known, though his history of conservatism in offense from Michigan isn't the greatest thing about him. And again, that's Jones's side of the ball.
I didn't know until I looked it up over the summer that Jon Jancek was Jones's defensive coordinator, and he was about to start his third year in the role. I only knew Jancek's name at the time because of all of the complaining Georgia fans did about him leading up to his firing in the Willie Martinez purge. I was legitimately surprised that Tennessee went with a DC who was a guy a division rival had decided was Part of the Problem. That Jancek was Jones's DC at Cincinnati explains it, but I don't generally keep track of the Bearcats' coordinators.
Jancek's Volunteer defenses improved over time, but they weren't elite. Clearly they weren't special enough for his name to come across my radar until I went looking for it, and I follow SEC football far closer than the average fan. For goodness sake, Jancek was one of only three coaches on the 2015 Volunteer staff not to have a Wikipedia page. It was him, the tight ends/special teams coach, and the strength coach.
From the point of learning about Jancek's role and on, I never totally took Tennessee seriously as more than a division contender. If the coordinator who does the opposite thing of the head coach isn't notable enough to merit a Wikipedia page after years of work, he's probably not going to be good enough to put you over the hump. The SEC East is so down that I didn't think a division title was impossible, but anything beyond that probably wasn't going to happen.
Tennessee parted ways with Jancek this winter in what wasn't phrased as, but mostly feels like, a firing. The defense giving up big leads late in games was a problem a few times this year. It couldn't have been easy for Jones, who has a track record of loyalty to colleagues. I think it was the right call given the program's ambitions, though.
Even more important than that, Jones nailed the replacement hire. He pulled Penn State DC Bob Shoop, who, as it happens, does have a Wikipedia page. Shoop served as DC for James Franklin at Vanderbilt before taking the same role in Happy Valley. His defenses were easily the best aspect of Franklin's Nittany Lion teams, and his Commodore defenses were a big reason why Vandy made three straight bowls.
In short, Shoop is the sort of defensive coordinator that I can see leading a championship caliber unit. I still have my doubts about DeBord, but that is still Jones's side of the ball and he's running Jones's offense. The defense, however, is now in the hands of someone who can truly take things to the next level.
Tennessee was probably going to be the offseason East favorite by default, between Florida's heavy NFL Draft losses on top of its mediocre post-October performance and Georgia starting over with a rookie head coach. Toss in the return of stars like Joshua Dobbs, Jalen Hurd, and Derek Barnett with a bowl bump from thrashing Northwestern, and it will be hard to find media outlets picking anyone but the Vols this offseason.
I very well could end up one of those people picking Tennessee to take the East. Again, that's not that high a bar, but it's still an important step since UT hasn't been to Atlanta since 2007. However with Shoop taking over the defense, I will now have to consider the possibility of the Vols winning in Georgia Dome both this year and in the future.
For that reason, Tennessee grabbing Shoop is the biggest hire of the offseason. Other East division teams should be worried about this development.