Hermann bring a long and successful resume having been a defensive coordinator for 9 years at Michigan before moving to the NFL. He was the Jets LB coach for 3 seasons and has held the same job with Giants since 2009.
He's been a part of winning almost anywhere he's gone. He won a national championship at Michigan in 1997 and a Super Bowl with the Giants in 2011. After that national title in Michigan, Herrmann received the Frank Boyles award for the top assistant in college football.
It would be a little bit of turnabout for the Eagles to grab the Giants LB coach as that's what New York did with Steve Spagnuolo and it played a big part in them winning the Super Bowl in 2007.
It's hard to know a lot about how much impact a guy has had as a position coach, but Herrmann's resume looks strong and he has a lot of coordinator experience at the college level. Seems like a strong candidate.