I don't think the 4-2 translates to better run defense, at least for us. What we do with the 3 stud lineman fives us enough to clog everything up and let aggressive, mobile LBs and safeties get to the ball carrier sooner and cleaner.
I think bringing one of the safeties up closer is the better response, especially with the hammers we have at safety.
Which is exactly what we did against WVU.
My bigger concern for the young LBs is dropping back into pass coverage, we got chewed up there a bit but I think the youngsters had it figured out by end of WVU game. I just worry about running out of youngsters.