I think Urban is just keeping certain units on their toes. We know he's not afraid to praise certain groups for different things (focus, work ethic, trust, togetherness, etc..), but he needs to see it consistently on Saturdays. The off season work needs to translate into tangible production.
I agree with Spielman on the fact that the line will make the unit better. I loved playing linebacker in a 5-2, see ball - get ball. Once I got older having people in my face changed everything. Wasn't until I moved to safety I truly understood how linebackers need to read keys to put themselves in position to make plays. If one or more of our thoroughbreds up front demands a double team, watch out.
The D lines dominance should and will hopefully have a 'trickle back' effect and make the whole D dominant.