I think our problem on D is when we face teams that can pass and run well. We can't defend elite runners without bringing up the corners and safeties to help. Then we get burned by the pass... Defend the pass and linebackers get burned by the RB.
One Darius play... (smarter, less lazy) would stop inside runs allowing linebackers to contain the edges and safeties to maintain their depth. Mean while De would have a better chance to get pressure