Yea interior DL is about as big of a issue as the secondary. Hard to call which is worse.
Basically anyone with any ounce of competence on oline pushes them around up the middle.
If the ends/blitzes cant get to the QB that secondary is cooked.
Its a combo of mostly failed recruiting at certain positions (or players transferring out) and poor player development. Don Brown's style just doesnt fit. It might work against the crap teams like Rutger and Maryland but the better teams exploit the fuck out of him.