As the Eagles search continues for their next defensive coordinator, several names have been mentioned, most recently Jim Herrmann, who is currently the linebackers coach for the New York Giants.Herrmann is known to be an “old school” defensive coach, and played and coached (defensive coordinator) under legendary Michigan head coach Bo Schembechler, who was about as “old school” as it gets. During his time as Michigan’s defensive coordinator, Michigan routinely had one of the nations best defenses, and put several players into the NFL.As per Reuben Frank’s report on CSN Philly, Herrmann was brought into the NFL in 2008 by then Jets head coach Eric Mangini. When Manginia was fired, Tom Coughlin hired Herrmann, and he would eventually win a Super Bowl with the Giants last season.One thing that’s good about Herrmann is he would most likely run a 4-3 defense. It’s been rumored that if the Eagles brought on Todd Grantham from The University of Georgia, that he would bring in a 3-4 scheme.The trouble with running a 3-4, is that the current defensive, in particular the defensive line, is already built for a 4-3.I guess it doesn’t matter if the Eagles plan on blowing it up anyway, but it would certainly be easier to bring a guy in who runs a 4-3 given the fact that the Eagles are a bit undersized up front. Most of the defensive line is closer to 300lbs than 330-340 which is a problem because in a 3-4 scheme, the defensive lineman are usually responsible for two gaps, and have to constantly fight off double teams.What happens to guys like Trent Cole, Vinny Curry, Derek Landri, Ced Thornton and Cullen Jenkins?Antonio Dixon is really the only guy who has the size to play on a 3-4 defensive line.The other unknown in a 3-4 is what are you doing at linebacker?Obviously Brandon Graham is a natural fit since he already played that position at Michigan (and flourished in it), but we’ve never seen Trent Cole in space before. I’m not sure you can take a guy like Cole at this stage in his career and ask him to change his role. We all know how that worked out with Nnamdi Asomugha. They guy went from a Pro Bowl player to one of the worst players on the team.If you move to a 3-4 what happens to DeMeco Ryans? Remember, the only reason Houston let him walk is because he really didn’t fit a 3-4 defense.Do Jamar Chaney, Akeem Jordan and Mychal Kendricks have the size to play in a 3-4? That’s debatable.We all know the secondary needs major help, but if they move to a 3-4, it means that entire side of the ball gets blown up.I know the offense is expected to score some points, but they’d have to be a top 5 offense to get by with a 25th+ ranked defense next year, which is likely to happen moving to a completely different scheme with a big personnel turnover.I know the defense had major issues this year, but despite them, they finished the regular season ranked 15th in total defense, which is much better than both the Falcons and the Patriots, who could very well be playing each other in the Super Bowl in a few weeks. That quite frankly, is amazing.Imagine what they could do with a new attitude, and a couple new cornerbacks.