The offense doesn’t seem overly conservative, most of what I’ve been watching are the types of formations and calls (which run/pass concepts) he seems to prefer and the way he tries to run constraints. I’m sure Zimmer was in his ear but he’ll have a defensive-minded HC here.
I don’t plan to watch the Broncos games, to your point he was picking up someone else’s bad offense mid season. At least with the Vikings you know he installed that offense from day one, and I doubt Zimmer was putting his foot down on the specific concepts Kubiak was allowed to use.