For years and years, NFL scheming has been all about trend, counter trend and counter counter trend, with lots of herd mentality thrown in for good measure.
The West Coast Offense was a means for countering big physical defenses. It relied on a lot of short stuff with quick passes out of the backfield to the HB and FB serving as surrogate "running plays."
This was countered by the zone blitz which disguised coverages in order to confuse west coast style QB's who had to make quick decisions.
Which in turn has been countered by stretch running plays off zone blocking
To counter that, you're seeing more and more mix & max multiple fronts which require DE's and even NG's to drop off in coverage. You need faster defenders if for no other reason than to cover a teammate's six when he's pulled out of position to implement a bizarre or unorthodox coverage.
A parallel thread has been also occurring - less reliance by some (but not all) teams on big physical run stuffers at MLB and DT in favor of penetrating and pursuing interior linemen and Mike backers who can cover RB's and fast TE's like Vernon Davis down the seam.
The pendulem will continue to swing back and forth with each counter move. Right now the trend is toward speed - until someone like a Tom Coughlin figures out that if (a) your offensive line is big, strong and tough enough and (b) you've got Brandon Jacobs running behind it, it won't matter how fast the defense is - they'll just bounce off your players.
And then some team will counter that by putting two 375 pound beasts in the middle of their defensive line again and so on.
If Clancy P and Wiz want to rework the defense on the way to a 3-4, they would have to get faster, somewhat smaller players. But - unless you want to rip apart the defense altogether and start fresh (precisely what we don't need during this period of coaching transition), it's going to take some time - maybe as long as 3 or 4 years; with the changeover to those types of players occurring mostly by attrition (at least at first).
Drafting someone like WIllis to play Mike or SLB would be a terrific start since we have a hole to plug at SLB (that could be done by putting Willis over there or moving Hayes over there). Only thing is - we need to upgrade our O-line and someone like Thomas or Brown might take precedence in round one.
In the second or third rounds, we could probably find ourselves a speedy CB who could learn his trade behind Rolle and Hood while competing with Green for nickel and time time. (Green already has the speed, and Rolle isn't all that slow either).
I realize we're probably now set at safety, but i'm intrigued by Meriweather because he runs in the 4.4's and could also give us more speed as a CB. Here's an unorthodox Belichecky kind of move - consider drafting Sabby Piscatelli in the second or third round. He's listed as a safety who runs a 4.51 but weighs over 220 lbs and sure looks like a mobile, agile and hostile LB. Let him play WILL and keep Dansby at SAM.
Think of the transition to a faster overall defense partly involving adding faster reserves who would be groomed to step up when they're ready to beat out a possibly slower starter ahead of them. That, in my opinion, would be how we'd get from Point A to Point D.
Note - Over on offense, I'm still intrigued and tempted by the possible drafting of Ginn (who could terrify defenses because of his deep speed and thus help take the pressure off Fitz and Q) but I think our other priorities (at LT and SLB) are greater.
