ESPN's Bucky Brooks has a nice piece on defensive trends.
It's a little simiplistic and most of this you already know, but some good tidbits, and of course, a little love for Ware.
A couple of highlights...
Linebackers are easier to find in all stages of the draft than bulky defensive linemen, and some teams have had success converting undersized defensive ends into rush ends/outside linebackers -- for example, Joey Porter, Adalius Thomas, Shaun Phillips and DeMarcus Ware. After watching those guys rip up the league as 3-4 outside linebackers, teams are looking to find more such athletes.
You only have to look at the dramatic rise of the Colts' defense after the return of Bob Sanders last season to appreciate the impact of the safety position. With Sanders out most of the year due to injuries, the Colts dropped to last in the league in rush defense. After he came back, the Colts ranked first in rush defense and scoring defense on their way to a Super Bowl title.
It seems unlikely that one person can impact a defense so much, but the safety position has increased in importance. With teams still using Tampa Two or Cover Two as their primary defense, the safety has become the "playmaker." Teams want players with the athleticism to cover half of the field in the passing game and the toughness to be a factor versus the run.
And finally, something I thought was interesting and new-ish...
The emergence of Cover Two and the zone blitz scheme have minimized the need for a "shut down" corner on the roster. Both schemes place a premium on pressuring the quarterback and emphasize the importance of pass rush over coverage.
Looking at the roster of the last four championship teams, New England's Asante Samuel is the only player who would qualify as a "shut down" corner. In fact, when examining the rosters of the top ten defenses, only Rashean Mathis, Chris McAlister and Nnamdi Asomugha possess "shut down" corner qualities.