there is one big, noticeable difference in the defense between last year and the great "shut it down" years from 2010 to the onset of probation.
those earlier teams used the defense to wreak havoc, creating live ball turnovers & turning them into fast breaks which fueled the offense. according to the data at kenpom, each year of that stretch, the defense created turnovers on over 13% of opponents possessions and was ranked in the top 10 nationally in to% each year.
last year's team created turnovers on a bit over 10% of each possession - very good, and good for 27th nationally, but quite different from those other teams. there is no data to support this, but my impression is that last year's turnovers included significantly fewer live ball turnovers - a lot of shot clock violations and bad passes that went out of bounds. the defense last year was a grinding defense that wore down opponents' minds. i'm guessing that a lot of that had to do with the lack of depth; the defense was a little more passive than previously as the defenders were not able to be quite as active due to the amount of minutes they were playing.
i'm hoping the added depth this year will allow us to see a return to the weaponized defenses of the first half of the decade and, with it, an increase in the lethal transition offense that it brought with it.