Idk, I feel like GC's coaching style and his entire program approach is so distinct from every other coach I've seen that I would be surprised if we could just plug in a "better" DC and see the kind of results you might expect. "Better" DC's are probably used to doing things like yelling at their players when they screw up, having a depth chart, benching people, etc. I don't know how much of that is actually going on, because I don't know nothin' at all, but from way out in orbit, it sure seems to me like we do a lot less of it than other teams do.
I'm not sure what our defensive staff is doing to correct problems they see on film each week, primarily because none of them are getting corrected and in fact the defense is getting worse every single game now. If we brought in a new DC, would he be able to use his methods, or would GC intervene to protect the environment he has set up for recruiting purposes? Not a question I know the answer to, but it's a question I have when I think about replacing just the DC.