O: Empey, Hoge, Gunner (last game, anyways)
D: Tonga (last game, anyways), Ah You.
Those are some really, really important players for us.
And on offense we lost our #1 star & a very promising RB too close to the start of the season to have reasonably adjusted for. And we've also been without a Corner who started most of last season for us. Those losses might not so directly effect the suggestive trends you're pointing out, but they have affected our durability as a team, probably. And that probably manifests itself in terms of inconsistency.
Personally — though it may not show up in the most simple game-to-game stats, I've been impressed by the resiliency & toughness of this team. I think if we'd pulled out the man coverage & pressure blitzes against UTSA we woulda cleaned their clock pretty good - but we also woulda exposed something we always had reserved for Houston as a surprise.