If we go through the year and a DL ends up being our leading tackler, I think it will be a good indicator that our D isn't anywhere close to where the coaches want it. The LB's as young and inexperienced as they may be really need their play to improve if we're going to hang with the pass happy spread offenses in the Big 12.
If our passing defensive statistics are poor, then you should come to the conclusion that we need more production out of the back 6 or 7 guys. In that case, you could argue that having a defensive lineman leading the team in tackles is further evidence of that. Considering the overall team statistics so far, though, I think it's encouraging that we have a productive defensive line, and a dominant member of that line who is leading in 3 statistical categories.
Looking at tackling totals, I think the only type of statistic that is always inherently bad is when your safety is the leading tackler.