Who said it wasn't impressive, I have no way of knowing that. Obviously Lester thinks a lot of him. That's not the point. The point is the level of risk of putting this person, however good a teacher and coach he is in general, at this PARTICULAR job.
That's it.
People can bring up Chip Kelly, Gus Malzahn, Nate Hackett, Tim Lester all they want, but they all had relevant direct experience for the positions they were hired for.
Shafer is running the program, he knows the people involved, the guy could be another high potential hire and this was the first, best way to get him on the staff. That's all goes into a hiring decision, but he is also rolling the dice that this won't be too disruptive.
Two years ago there was decades worth of BCS and NFL experience coaching the OL, and I think it showed in the turn around in that group from where it was in 2009 and before. Proof that coaching matters. It took a couple of years but the last two years that group both pass protected and run blocked as well as any unit this school has had in a very long time.
This hire represents 0 years of experience at any level. That's why there is concern.