I look at it this way -- what was WVU to do? They hired a guy who came in and completely remade their program from top to bottom. He had unprecedented success. He leaves and what do you do? Essentially hire a guy you think has a pretty good shot of sustaining at least a good share of that success or go outside and take a chance a coordinator or up-and-coming young coach? I'm not sure what the answer is but I really don't think you can blame them that much for hiring bill stewart (who, by the way, went 28-12 in three+ years -- it's not like he was an abject disaster).
I think the same is true for SU. You have a program that endured some truly uninspiring play near the end of the P era, then hit a nadir in the Grob era, then limped along inching its way back toward respectability under DM until finally appearing break through in the last 7 weeks. So what do you do? Interview a bunch of guys, maybe settle on one of them or hire the experienced DC who has a good resume, has produced some good defenses and actually wants the job?
I don't really think there's a *right* or, by extension, a *wrong* answer here.