Tennessee is not anywhere close to being a sleeping giant. Sleeping giants don't have to rely on all of their rivals being crippled by sanctions or inept coaches. Texas. Southern Cal and even Miami are true examples of a sleeping giant.
For Tennessee's recruiting to get anywhere near what it was under Fulmer's peak, Saban, Richt, Spurrier & Muschamp are all going to have to leave the SEC. Southern Cal & Notre Dame are eliminating the top tier national recruiting that Fulmer used to rely on, so even that is gone.