It doesn't matter that Dennison was running Kubiak's offense in Houston, because Dennison was running a version of it in Buffalo. If you're going to attribute Tyrod's weak passing to a deficient WR corps, what would you call Foles' supporting cast in St Louis?
You saw a glimpse of the passing offense design being more dynamic with Peterman under center, and I will argue that Foles doesn't throw wounded ducks that are ripe for picking. There's a high probability that Matthews is far more effective early on with Foles as QB.
Bottom line is that TT has led to 2 OCs getting the boot because he's not really a good QB