With the exception of some notable games by Kindle/Orakpo, I don't know if we've ever seen as dominating a defender as DJ at Texas since 2004. It was like having 2 extra players on the field when he was healthy. And when he wasn't healthy, it was like the Cowboys & Sean Lee phenomenon. The 2002 game against Tech that cost us a trip to the conference championship and a BCS game was marred by injuries on D, and even though Johnson was hurt, he still put up 9 tackles in a game where we gave up like 600 yards.
Honestly, I'd put Nobis and Johnson on the same level for what they accomplished both at Texas and in the pros. It's almost like a "Wilt vs. Hakeem" kind of situation. Nobis was so ahead of his time for a guy who could weigh like 240 and run like he did. I also think Nobis was surrounded by better players and played at a time when teams ran 75 percent of the time, thus the much higher approximate value for DJ in the pros.