that how the D responds is totally on the coaching staff. They no longer have the players like Miller, Ramsey, Floyd and other vets they brought in to be the "field generals". This season is all on the staff to be the best that can be and teach, monitor, lead, develop the entire D (outside of AD).
The entire defense is an unknown, some show (ed) promise in part last season, but in reality they are all unknowns.
IMO a true 'throw 'em in and see how they swim" year. And it could turn into a continuous every year looking for players or as easily become a good foundational base with not hope for improvements but actual abilities coming out at the get go.