So as a quick side-project I looked into UT's average scoring margin over the last few years. To give it some context, I did the same for the whole SEC from years 2012-2015 and then ranked the teams based on the results. I can post the data for the whole conference if desired, but for now, here are the numbers for Tennessee:
2012: -2.9 (rank: 10th)
2013: -9.7 (rank: 12th)
2014: +2.2 (rank: 10th)
2015: +8.6 (rank: 6th)
Some comments: this doesn't necessarily mean a ton. It's not a replacement for wins and losses, and it's not a replacement for watching what we see on the field. It doesn't account for strength of schedule, and this point in particular makes it fairly useless on a national scale (the Big 12's numbers, for example, look very different than those of the SEC simply because of the difference in playstyle). But when restricted to the SEC, where the teams generally play against each other, I think it has some value.
The "average average margin" - in other words, the yearly scoring margin for the entire SEC - hovers between 4 and 5 over the course of this sample. This year, it is ~4.2. So 2015 (to date) is the first time in at least the last four years when Tennessee outperforms the SEC average.
Dooley's most talented team couldn't achieve a positive differential. When the offensive talent from that team graduated, we bottomed out. Last year, we got back to a positive differential; this year, we're back in the top half of the SEC. Despite the frustrations of the first half of this season, we're on a clear upward track.
For reference, our next two opponents rank 11th (-2.9) and 13th (-6.7) in the SEC.