I think the Browns' greatest improvement this year is rush defense, particularly when measured by YPC, where we're at 3.9, in a virtual tie with a bunch of teams after the top 7. Pretty impressive, given our recent history. The result is that we don't give up a lot of points... we're edging toward upper third in scoring defense.
The pass defense is showing signs of coming along, understandable with so many new faces. The defense will need to deal with ILB, DE, and probably add another pass rusher type... not all that much, really.