As a point of confession, I did focus more on the skill-players than anything else. Maybe it's the allure of offensive prowess, but here's some quick notes I took about the defense.
1) Ndondo-Lay seemed to be making a name for himself out there. He was disruptive, and knifed himself in the backfield on a couple of occasions. Looks to be a solid player if he can get some PT.
2) Hard Legania was hard to miss. He looked like an enormous MarQueis because of the flowing dreads, but he also asserted himself as well. He was disruptive at times, and had some nice TFLs. Ekpe (can't remember which) also had some nice blow-ups in the backfield.
3) Once again, the second-string DBs looked great yesterday. Jalen Myrick was speedy, and blanketed himself on Drewski after initially getting beat. He has some nice closing speed for sure. Marcus Jones also looked the part. I think Travis ended up playing a couple snaps, but I didn't see much else from the starting DBs. Once again, props to Sawvel and the rest of the staff for really bolstering the unit. Steven Montgomery had some playing time-- not sure how that comments on his development from last year where here he was lighting it up in the Spring.
3) With the 1st D out, a lot of the younger LBers got some playing time. Couple names that were consistently mentioned included De'Niro Laster (or "Lanter", as the announcer kept saying), Ray Dixon, and Chris Wipson. Wipson had a nice blow-up tackle on a running play that got some cheers. I saw Matilus line up a couple times as a rushing LB/Hybrid DE-- not sure if that's indicative of a new wrinkle on the defense or not.
4) The defense gave up big chunks of yards, but held solid in the short-yard and goal-line situations. I suppose the complete opposite of a traditional 4-3, so take that for what you will.
I didn't think it was nearly as defense-dominant as others have mentioned. Then again, since there wasn't really much of a game-like structure to the scrimmage (no teams, seemingly extra downs), it's really hard to take anything too concrete out of it.