UK improved for sure over these last 5 or 6 years, but clearly disappointed after obtaining their highest ranking since Fran Curci (I may be mistaken there) was coaching there.
With that said, UK truly benefitted from the simultaneously timed decline of opponents UL, South Carolina, Missouri, UF and even UT to a lesser degree; each one rebounding. Add in their additional mild non-conference schedule and it explains in part their success.
Huge and talented Offensive Lines and extremely powerful RBs sure contributed as well. I do give Stoops credit though, as clearly he made that team much better than what he inherited.