There are actually some bigger names being bandied about (Chavis, Chizik, Brady Hoke), but as long as Shoop isn't hellbent on bringing the 3-4 to Knoxville, I think he's my first choice. He has a reputation as an innovator, and will install some really creative coverages and blitz packages.
There is no way now how Chavis could return. He's knee deep in buyouts and lawsuits and contractual obligations. Just not even a possibility.
Brady Hoke obviously has a ton of coaching experience, but he hasn't been a defensive coordinator since 1982, and that was at the high school level, and he hasn't recruited the Southeastern US as a recruiting base ever.
Chizik? Obviously a good candidate, but the chances of his taking a head coaching job soon are pretty high.
So, Shoop makes a lot of sense and he is a solid DC and has recruiting connections in the Southeast, and particularly in middle Tennessee, where it is going to be a great year in 2017 and a place that UT needs some help in repairing some bruised relationships.