I'll give Willingham credit for bringing in Sullivan and Harris in 2003, thanks to the momentum from 2002. Both proved to be long time starters and yes, even in the NFL, but never reached their potential until 2005-2006.
His 2004 class, though, had two O-line commitments in the way of John Kadous and Chauncey Incarnato, who never panned out anyways, since they left before the 2005 season even started. They weren't exactly highly sought-after recruits either, where Willingham's passive recruiting almost destroyed the program.
2005's line commits, Paul Duncan and Mike Turkovich, were both brought in by Charlie Weis. They at least turned out to be serviceable starters.
2007's miserable season would have been a rotten one for any coach out there. Even Nick Saban or Urban Meyer would have only gotten us to maybe a 5 or 6 win season with that roster, thanks to the absolute lack of true junior and senior athletes on that team. For that matter, when you put a bunch of still-raw freshmen and sophomores against well-developed teams the likes of that 2007 Michigan team, it was a recipe for absolute disaster.