Here are the OFEI's of the teams we've face (WCU not included) For comparison, our offense is 107.
Clemson - 42,
Ole Miss - 8
UCF - 24
Pitt - 69
Duke -38
UVA - 100
FSU -18
VT -108
Against Clemson we had held them to 14 points midway through the 3rd quarter until Thomas got ejected (and 7 was basically off a punt block). Then things fell off, along with getting worn down because of the offense.
Against UCF, we had held them to 16 points through 3 quarters, with 7 coming off a punt block, until again Thomas was ejected. Overall, I'd argue this game was the most impressive defensive performance of the year. Pitt isn't as good offensively as people believed at the time (although we did go without Thomas the first half), and maybe you could argue Duke, but they've played such a weak schedule that it's hard for me to buy it.
The Ole Miss game was terrible, but so too was FSU, and the Virginia schools are so bad offensively that I'm not sure how much that says about our defense.
Overall, the defense is improved from last year certainly but I think that was shown even in the first 4 games. But we were, overall, playing better offenses and also spent a quarter of the time without Thomas. I think a good part of that is personnel, which obviously hasn't really changed mid year. Thomas has taken a big leap this year but that also was shown from game 1. We've been better about getting negative plays from our opponents, but again, that was true in the early games (White had 4 of his 4.5 sacks the first 4 games, Eley 2 of his 3.5) TFL numbers also support this. Turnovers are probably the biggest difference between this year and last year. We had 8 through the first 4 and have had 22 through 9 for an average of 2.4. In general turnovers certainly have an element of luck, and it feels we've gotten quite a few gifts this year in that regard. Similar to how in 2014 we were really good in forcing turnovers with Roof, but it was never repeated with him and in general it was a weakness.
Had we not looked so bad against FSU and if we look competent against UNC and UGA I'll be more of a believer, but I think the talk of keeping Thacker on seems based on hope and performances against weak offenses rather than real improvement (since Collins was fired).