@GTFLETCH already has:
https://www.stingtalk.com/board/threads/too-soon-to-pull-the-plug-on-cpj.89993/page-3#post-1858389
Roof has basically 2 recruiting classes on the field at this point. He has been a part of 3 classes, but consider that pretty much all of his 2016 guys are redshirted. Of the guys in his classes that are playing, 12 guys on the 2-deep did not redshirt, i.e. they played as freshmen. So, we are behind the curve a bit from a maturity level.
Also, according to the 2-deep, there are 6 guys from the 2012 and 2013 classes. SIX. TOTAL. At least 10 of the 22 guys on there should be 4th and 5th year guys. I just glanced at Pitt's depth chart and they have 11 guys that are either RS JR, SR, or RS SR. And their chart even goes 3-deep in some positions. Other schools will show similar situations.
Additionally, we all know that our recruiting has improved under Roof, dramatically in some cases. Let's not forget that one of our starters on the DL (until recently anyway) was brought in on sheer potential, and has not panned out.
So, we have a dearth of upperclassmen, the guys we do have playing are a year younger than would be preferred from an experience standpoint, and our upperclassmen that we do have are not as talented as some of the guys are we getting now. Those things combine for a real problem from a depth standpoint.
My takeaway, and I hope yours as well, is that Roof is raising the bar on our defense. But it takes time to overcome the barren cupboard he was left with. He's bringing a strong class this year, and I think the next two years will show an uptick in defensive performance similar to what we've seen from when he got here until now.