Purdue's defense was relatively young last year, especially late in the season. They used a couple of true Sophomores at DT and NT, a True Frosh (Bentley) at MLB, Redshirt Frosh (Ezechukwu) at one OLB and a redshirt Sophomore (Herman) at the other OLB spot. One CB (Brown) and one Safety (Williams) were Juniors. The DEs were both Seniors but underperformed in terms of pass rush (one did get drafted by Dallas however). That youth probably accounted for that lack of blitz disguise as they didn't try to do too much in the way of exotic schemes, just tried to execute some of the basics.From what I noticed about Purdue defense is they don't really disguise blitzs or coverages and will play pretty straight up. Also their top pass rusher is suspended for the game
This season, one of the safeties, Williams, has moved back to his normal position of CB and the likelihood is that the new safeties will both be upperclassmen. Purdue has a promising true Junior, Panfil, taking over at one DE and brought in a JUCO, Henley, who'll likely start the season at the other DE/Rush LB position. Purdue's best D-lineman, in terms of TFL, is actually their DT, Replogle. Tops in sacks was who's expected to start at NT this season, Watson. The LBs all return and now have another year of experience (and in Bentley's case, a Frosh All American award) under their belt.
No telling if they'll be good, but they should be better than last year.